Intro

Hi there, my name Atmoist and I'm a ****ty Nasus top main. I'm low elo (high silver, trying to push gold this season on a couple of accounts).
Yeah, fair enough I'm not the best but I've tried to make the notes and guide for this build as in depth and helpful to players around MY skill level as possible.
If you want a pro guide this really isn't the place to be, but I feel like for people my level this guide can be very useful, as in higher level guides a lot of the macro play is assumed, but I will try to point out these smaller things that you could do as you get better in this elo.
I main Nasus top in ranked, I don't play JGL and especially not Carnarius wacky AP supp build lol.
P.S. Most of my thoughts on how to play Nasus are found in the notes sections throughout this guide so make sure to read them for more in depth thoughts/guidance on what my mindset is for each choice.

Top lane

Gunna put this at the top so more ppl see it:
Don't use Grasp for god sake. Please read each runepage and realise it is the worst choice some Nasus players use now. Evey other runepage I have put for top lane is better.

Top lane on nasus is all about wave control and stacking. If you can't stack try to finish minions with your E without messing up the entire wave. Freeze near your tower for as long as possible and stack stack stack.

If the enemy dies early try to slowpush before backing, but later on when you have better waveclear try to fastpush to get some tower plate damage before making your back.
If you don't know how freezing, slowpushing and fast pushing works, search up a yt video but the tl;dr for it is:
Freezing: Try to only last hit minions and if you run of friendly minions/enemy pushes to your tower use ur body/hp to take the minion aggro and position them just outside ur tower range. This is really where you wanna be freezing your wave and will net you a lot more stacks.
Slowpushing: Slow pushing is good for building up a big minion wave to crash against the enemy tower, optimally before a back. You can do this by targetting the spellcaster minions first and killing them asap. This will mean your wave takes minimal damage but is frozen by the remaining enemy minions (you can finish them off when they get to one shot), allowing your next minion wave to catch up and creating a much bigger wave.
Fastpushing: Fastpushing consists of just killing the enemy minions as fast as possible to get your minions under turret as fast as possible.

I aim for about 100+ stacks by 8 mins at a minimum, this means I am normally on track to be able to 1v1 most top laners, the higher the better though, however don't panic if you don't maintain this, just focus on your farm a bit longer and potentially sacrifice roams you might have otherwise taken.


Invading the enemy jungle:
This can be very beneficial for Nasus, especially if you are on the red side. The enemy jungle will consist of blue, gromp, wolves and scuttle (if it's up) if you know for a fact that the enemy has camps either up or coming up in time for you to make it there, consider stealing gromp, scuttle, the big wolf and blue. Each of these will net you 12 stacks each, 48 total, will deny the enemy jungle their much needed blue/farm and is hard for them to react to if they catch you doing it, potentially getting you a free kill.
I would mostly do this if you wave has been shoved so it's hard for you to farm or if you see blue is coming up in the next 20 seconds.

Pushing tower
Pushing towers on Nasus is crucial. If it's pre 14 and you see your enemy appear in bot or back without TP use your E and fast push that turret. This is why maxing E is so crucial IMO, you would not otherwise be able to really do this at all, as your wave clear can be very slow without that damage at this point. As Nasus, you can really punish top if they decide to disappear and give you space. You can either farm like crazy if you're a bit behind or shove that tower and get **** tons of gold that you need for your powerspike mid game. Each plating is worth 160 gold each, netting you a total of 800 gold. If you can finish it off you will get an extra 250 gold. If you're the first person in the game to destroy a turret you get another 150 gold. That's 1200 gold if it's not split with your jungler. This can be massive, it's worth more than a 700g bounty and worth about 8 whole minion waves roughly (based on 14 min minion worth)
If you can't see how huge this is for your powerspike, wake up. Use your ult if it's safe to do so and you want to back soon, it doesn't have a long cooldown and will double the rate at which you can melt that turret, Nasus is amazing at pushing towers.
If the gold isn't worth it for you, remember that destroying top tower applies a lot of pressure to top and allows for much easier ganks for your jungler or midlane if they roam up. This can allow you to roam in a game much more.

Vision and roaming on Nasus is also very important and you should be thinking about it constantly.
Vision:
I always buy a control ward on every back I can, only sacrificing it if I'm really strapped for cash and only have enough to buy the item I specifically backed for. Even if you already have a control ward down, doesn't mean you shouldn't buy one. You might need it during a roam and your top river control ward gets taken very often either by enemy top or the jungler. Controlling vision top is crucial for Nasus in my opinion, you are very vulnerable early and if you manage to **** up a freeze or shove a wave too hard resulting in an enemy freeze, you are in a very vulnerable state and need to know if you can get away with farming, or if there is an immediate threat from the enemy in the river. Using your stealth wards is also a no brainer, I often find myself using my first one in one of the top bushes if I'm against an enemy that is most likely hiding there and waiting for me to farm in a vulerable state on the first wave. Just use your minions as cover and chuck one in there if you think this might be the case (Also check bot, if enemy bot hasn't made themselves known and your lane hasn't they are most likely in a bush). Otherwise just use your stealth ward as you see fit.

Roaming:
Roaming is a tricky one for new Nasus players, it's very easy to hyperfocus on your wave control and your stacks and not watch the map. You might be weak early but if your jungler gets into a pickle early then 2 bodies against 1 is a much better alternative to your jungle inting, even if you can't do much damage. Just be weary of your lane following you and be sure to cut your losses and just try to get the enemy jungle off your jungle if need be.
If you are running TP this obviously gives you a lot better map prescence and roam potential throughout the game, same with spellbook, so make sure to use it appropriately if you see a dragon fight coming, especially if your laner is going to be present there.
As Nasus you really can sway the tide of a teamfight, especially once you have the core items (sunderer and gargoyles). If you have ghost up and these 2 items you can tear multiple enemies apart with your ult in a teamfight scenario so make the most of this especially in the mid game when you are starting to get strong. Even if you feel like you're not doing much to the enemy top laner and ur stacks just must be too low, they are most likely the tankiest person on their team, and you likely have enough stacks to squash a squishy in a few bonks so you need to try be at fights you can make it to in time.
Also helping your jungler grab Herald or doing it yourself will net you 12 stacks if they let you finish and can greatly help another lane so give them a hand if they ping you.


New notes after trying both my tanky build and lethal tempo more.

LT: Amazing for playing against someone youre confident you can beat. It provides so much more damage than fleet at the cost of sustain and manoeuvrability and having extra Q distance at max LT is so nice for running people down.

Tank build: this build is shockingly good honestly especially if you're low elo (bronze/silver). Playing with some of my newer friends with this build has been insane and has let me carry honestly more games than I normally could with standard meta build. Your fight potential early is weak but in this low elo you dont get punished hard for sunfire aegis procing and ****ing up your wave like you may at higher elos.
Your weak early game is made up for late game, as you're basically unkillable and have godlike tenacity due to sunfire aegis mythic passive giving you more and more tenacity, and your damage is still insane with ER and decent stacks. I also have mostly been running LT with this build to try make up for any damage lost and really turn me into a bonking inescapable monster late game. I genuinely think for low elo players this could be the build to go, Nasus already requires little skill but this just makes him godlike in low elo games where you arent countered well enough. Here is a pic of one of my test games with the build against bronze players where I got a penta with no damage items besides ER:

Primary Rune Options

Option 1 - Inspiration

Keystone: Unsealed Spellbook - Spellbook is such a fun keystone to run on Nasus with Resolve secondary (Need the tankiness really). I would always encourage Nasus players to use Flash + Ghost, and this keystone reinforces this by allowing 2 uses of tp per game.
Apart from giving you TP there are so many other uses for this keystone, as seen below:

Clarity - Refill your mana
Ignite - Potentially give you a very early boost kill
Heal/Barrier - Can be used to bait an attack from an enemy and then stomp them
Exhaust - They got some high mobility champ kind of fed in another lane? Roam down hit them with a W, then hit them with exhaust after W duration for a free kill.
Cleanse - Going into a fight where there might be some hard CC? Just wait for it to hit you and cleanse.

You can swap to a different summoner spell whenver your main ones are down in time for most teamfights

Magical Footwear - Think this is the obvious choice. We love free move speed on Nasus.

Biscuit Delivery - Biscuits will give you a nice bit of mana sustain, as Nasus is not only a mana gobbler anyway, but can be forced to chew through his mana if he's fighting a ranged champion even faster.

Cosmic Insight or Approach Velocity - I think this really comes down to your choice. They do completely different things.
Cosmic insight provides some summ spell haste and item haste, which could be very useful if you are going to be using a lot of ability items. I prefer approach velocity for it's movement speed boost towards impaired champions; just W and zoom fast as **** towards them even without the use of ghost.

Option 2 - Precision

Keystone: Fleet Footwork or Lethal Tempo - As mentioned previously in this guide the TL;DR of choosing between these runes is use fleet into tough matchups, lethal to absolutely squash and snowball in easy matchups.
Fleet Footwork provides some insane sustain throughout the game and is honestly just a better version of Grasp. Unlike grasp, it allows you to enter the front line, pop the passive and leave with a movement boost. Grasp just leaves you there vulnerable. The HP gain restoration from fleet throughout the game is amazing imo, and the small movement boost can help you in laning phase avoiding attacks, as well as in teamfights running opponents down.
Lethal Tempo is also great on Nasus and provides a lot more damage potential than fleet footwork. The playstyle is slightly different, where you are aiming to hit the enemy with a lot more basic attacks between Q's to build LT stacks. This rune increase attack speed and attack range which when combined can make you almost inescapeable.

Triumph - Getting some HP back every time you get a takedown is great for sustaining Nasus in teamfights

Legend: Tenacity - Even into low CC comps bring tenacity, it will deal with slight CC and really helps you out. The other 2 options are fairly useless on Nasus anyway

Last Stand - Last Stand is the obvious pick for Nasus. There won't be anyone with higher HP than you and you'll hit so hard that you won't even witness a damage increase on low enemies because they just pop. Last stand makes you a nightmare if the enemy even dares to try focus and take you down; often results in you taking at least someone down with you.

Option 3 - Resolve

Really don't recommend this RunePage as it's keystone and second rune aren't great/necessary on Nasus.

Keystone: Grasp Of The Undying - Grasp is like a nerfed version of Fleet Footwork; it doesn't provide any escape movement speed. Can be good into very aggro dumb top laners who let you hit them under your tower in a horde of minions. Basically a tank/sustain rune like Fleet but worse.

Demolish - You already destroy towers on Nasus. This rune could be alright if you wanna just split push all game but your Q does almost as much damage as when this procs.

Conditioning - Outstanding rune on Nasus. On most other champs I would say consider the other two but really you should be running this every time for Nasus. He is a scaling champ, so scaling runes like this really benefit him.

Overgrowth or Unflinching - Most games I run overgrowth, it is yet again another scaling rune. Pick unflinching into high CC comps.

Secondary Rune Options

I won't give descriptions of all runes here as you can just find all of them in the primary rune section above- there is a lot of cross-over.

Option 1 - Resolve

Conditioning

Overgrowth or Unflinching
IMO These are the go to runes for 90% of your matches- unless you're playing Resolve primary obviously.

Option 2 - Precision

Triumph

Legend: Tenacity
These would be my choices of runes to run if you're playing with resolve primary. Just 2 very strong runes.

Option 3 - Inspiration

Magical Footwear

Biscuit Delivery

Cosmic Insight or Approach Velocity
Quite fun secondary runepage, has some great runes to pick from. Mostly just comes down to how you play. If you think you won't need the tankiness from resolve secondaries then you could have some fun with this one.

Bonus Shards

I would recommend going ability haste shard, armor shard, health shard in most situations, swapping out armor for MR shard if enemy top is AP. Ability haste shard is the only real first row choice on Nasus top. The second choice is flexable as aforementioned. The health shard is my go to pick as it scales better than armor or MR shard. However, if the enemy team is heavily sided towards AD or AP then I might swap third row to armor or MR shard respectively

Itemisation

Gunna colour code choices here so you can choose what works for you:
Green - Health
Blue - Magic Resist
Yellow - Armor
Gold - AD
Dark Green - General tank (HP, MR, armor)
Grey - CDR
Red - Armor Pen
Purple - Anti-Heal/Healing
Dark Blue - Mana
The name of the item will be coloured with the most important feature, followed by coloured x's for secondary purposes.

Mythics:

Divine Sunderer x x- This mythic is the standard choice on Nasus. Sheen is essential to Nasus power spike and this item when full built gives him huge damage a lot earlier than he would otherwise be able to get it. Provides a good amount of health, CDR, AD and the mythic passive works well with Nasus, reducing the need for armour penetration items.

Trinity Force xx- Imo this is the worst "commonly built" mythic on Nasus as it is meant to be a direct stand in for Sunderer but does less damage and empowers him in a way that is not really necessary to Nasus' playstyle. It offers the exact same base stats of Sunderer, with 5 less AD and 30% attack speed. It's passives and empowered sheen are both worse, I guess it offers some ability haste as the mythic passive which could be quite nice?
Overall, this item simply doesn't fit Nasus' playstyle IMO. He is not an attack speed based champ and his main damage comes from his stacks/sunderer spikes better.

Sunfire Aegis - Honestly, Sunfire Aegis is my second favourite choice after Sunderer right now. In low Elo it can be shockingly good, as people will punish you less early. I normally rush sheen before I buy this item because I still think it is crucial to Nasus S12. This item makes you into a godlike tank and extending your powerspike much later than you would get with Divine imo. The stats alone are great, with armor, MR, health and ability haste and the passive's make you very strong in teamfights. The mythic passives, however, are what make this item great. At full build you will be getting 250 extra hp (so 600 total from this item), and 25% tenacity + slow resistance. This item really does just turn you into an absolute stat stick, which is what you really want on Nasus.

Legendary:

Gargoyle Stoneplate - Simply THE most important legendary on any Nasus build IMO. Great stats and that shield will allow you to get more fights before you would otherwise go down, while baiting enemies to finish you.

Essence Reaver x - This is for the sunfire build. You don't necessarily have to upgrade sheen but I think this item is honestly very good anyway on Nasus, especially considering it's price. It gives some good mana regen every time you use your Q, gives a lot of AD and ability haste for it's price, and having even 20% crit chance can be very nice on Nasus, it's just free bonus damage every 5 or so hits.

Fimbulwinter - Tear is a great item for Nasus early, pretty much getting rid of all his mana issues. Imo Fimbul itself is honestly kind of outshone by Anathema's chains after using both for a bit. They are health stat items but anathema's gives so much more health and also can mostly negate an enemy hypercarry. I mostly build this is they have good true damage, as getting that shield every W is very nice in these situations. Fimbul itself is primarily for HP but tear is mana item, thats why this is blue.

Anathema's - Amazing legendary. Gives ungodly amounts of HP while also allowing you to select a target who will now do much less damage to you. Use this when they have 1-2 big damage dealers especially.

Thorn mail xx - This is pretty self explanatory really. You often need anti heal in S12 as so many core items give omni or lifesteal. Buy bramble and finish into thorn as last item.

Spirit Visagexx - Makes your life steal from Q absolutely insane, as well as making you better against AP heavy teams. All round good items for if the enemy team is at all tilted towards AP heavy.

Force of Nature - This is the choice if you're playing into an extremely heavy AP team. If spirit is your mid ground, randuins is your anti AD, this is your anti AP. Offers extremely high MR with some health and move speed. Every spell used on you will also give you more movement speed. So in these matchups where you need to gap close against enemies with slows this is an amazing choice.

Randuins - This is the normal hard AD counter. Reduce attack damage and crit with active and enjoy reduced damage from passive and huge armor.

Serylda's Grudge x - Only AD item that should really be taken on Nasus besides ER or DS. You are meant to be a stat stick and your Q provides all the damage scaling you need. This item is chosen for it's armor pen if enemy is stacking late and for the slow which can be applied using your E on a massive area.

Steraks x - Used to be amazing but not so great since it was nerfed. Only really use if you are getting burst and need that shield

Frozen Heart x - People **** on this item but it's cheap for a reason. Provides some good armor but is only good against pure attack speed comps. It has it's specific use and does this job well but apart from this, try not to buy.

Boot picks
Imo 95% of the time you wanna just go lucidity boots for CDR and early at that. Rush them straight after you get sheen. If the enemy has a lot of CC you can just go Unflinching and Legend: Tenacity to help, but if you really need the MR and you didn't bring these runes grab Merc Treads. I also find it useful occasionally to just buy them once I'm full build/late game when I'm doing less damage and just being stunned all over the place. I only really buy plated steelcaps if I'm playing an especially aggresive AD top/JGL and am getting bullied/killed by them in lane.

Just going to chuck some good Nasus players who are much better than me in this section so you can look at their builds etc if you would like a more pro look into Nasus.

EUW

CarnariusV2 Arguably the top Nasus player on EUW. Currently Master.
He has a guide on here so have a look there for more of a pro guide.
His runes directly influence the runes on this build as I think of him as the standard setter for meta runes on Nasus. However, he has stopped playing top so much in favour of mid so keep that in mind when looking at his most recent vids/builds.
He usually uses Fleet Footwork or Lethal Tempo runepages as shown in this guide.

jorkkabob High elo mid Phase Rush player. Diamond 1.

Freud Neiman high elo Nasus player who uses many different rune pages in top. Masters.
This guy uses so many different rune pages and always starts Doran's Ring + pots. Very interesting player to have a look at. Uses everything from Phase Rush to Conqueror in high elo

NA

Psychopathic Top The Carnarius of NA. Probably the best Nasus NA who streams.
Runs mostly Precision builds found in this page, as well as sometimes using Conqueror

Can1ne Likely the highest elo Nasus OTP atm sitting in GM.
Absolute god who pulls off a Phase Rush + TP build.

KR

Meta is very different in korea, with a lot more Spellbook, Grasp of the Undying, and Phase Rush: the opposite of EUW/NA.
Just going to Post links of a few without descriptions here:

Summoner1 Spellbook god.
Summoner2 Spellbook/Grasp
just v Phase Rush/Conqueror

JGL

Find rune pages for this build at the far right of the rune page and by pressing the arrow once.
I'm not so well versed in JGL Nasus but here are my thoughts on it.
I use the same clear as another guide on here, that being:
Blue side- Red, Blue, Gromp, Wolves, Raptors, Scuttle, Krugs
Red side- Blue, Red, Raptors, Wolves, Gromp, Scuttle, RESET, Krugs
Nasus clear is very slow at the start so this order means we stand a fighting chance of getting a scuttle.

Jungle nasus, despite the slow start, is incredibly good at getting stacks fast, often almost doubling my average 8 min stacks in top lane by the 4-5 min mark. This might make you stack hungry but you do not need them. If top lane Nasus can carry at 16 with 300 stacks, when you get 300 at 10 USE IT. You can force very strong ganks pretty early especially if you have some move speed from ghost, predator or phase rush.

BLS Sundavr Diamond 1 Nasus JGL.
Runes:
Primary:
Predator
Cheap Shot
Ghost Poro
Ingenius Hunter
Secondary:
Legend: Tenacity
Last Stand
Shards:
CDR
Armor
MR

Carnarius AP Supp

Find Rune Page for this build by pressing the arrow on the runes and going to the far right page.
Kind of troll but I put this in here, props to Carnarius ofc he is best boi and most of how I play/builds/runes etc are mostly inspired by him and how he plays <3.
I wouldn't recommend ever playing this in ranked as it will most likely not work and will tilt your teammates.
You aim to use your huge AoE E ability on the enemy botlane, proccing Arcane Comet along the way. You do a shocking ammount of chip damage early and once you upgrade your E and get some items your E can be devastating even as a "support". Obviously you are much squishier than top or jgl Nasus and your Q is practically useless so if you're used to these lanes then you need to adjust your playstyle substantially. Your W is a horrible slow for the enemy to deal with so comboing your E whilst they are slowed will net you a lot of damage, and should allow for your teammate to get some nice easy picks.
Everfrost or crown could be alternative mythic items as everfrost provides some extra amazing CC and crown gives you more survivability at the cost of damage.
The passive damage from your ult can also be very nice if you stand near the target. The Ability page is obviously pretty troll as you will likely need your Q at least for shoving tower and it can help when you're ulting but this is just a copy of what Carnarius played so I'm sticking with it x).
As mentioned before, this was basically a troll pick but I wanted to just chuck it in here in case I or anyone else wants to have some fun in normals :)