I am a casual player and this guide is just to share insight and how I feel Nautilus is. I am not ranked and this guide is by no means troll or completely legit. It is a personal feel for him and you just have to judge on depending on experience. This is my first guide. Thanks for reading.

This guide is in progress. This is NOT a finished guide.

Why play nautilus? He's a ridiculous tank that provides large amounts of cc. His damage is pretty high for a tank and he has so much disrupt and versatility makes him threatening in lane and deadly as a jungler.

Heal- tanky and now you have even more health. can catch people by surprise when they think it's on cooldown. also great item to support with in duo lane.

Smite- must have on every jungler. secures buffs, dragon, and baron.

ghost- better chasing and escaping tool than flash if you don't count CC or walls. I prefer ghost on nautilus because you're usually tanky enough to get away even after the CC due to mercury's treads.

flash- short distance teleport chase and escapes. slightly more versitile than ghost as it can get you over walls. it is a personal preference which you take because some people just use one better than the other. some people also use one better depending on the champion. basically, take whichever one will get you the higher advantage to YOUR playstyle.

In laning, you want that anchor to pull away running enemies at level 1. This is because at level 1, you're most likely way tankier and can deal more % damage on them then they can on you. This is even more so if bottom against ranged ad/support. Getting anchor at level 1 has landed me many first blood's. After this, the 1 level riptide pretty much gives you your full cc combo (excluding ultimate). At level 3 you should be able to get the enemy down to red or first blood if no one has gotten it yet. either anchor>riptide>titan's wrath>autoattacks, or get close enough to riptide>titan's wrath>autoattacks and wait til they try to run to anchor and reel them back in.

In the jungle, you want riptide first since it has the lowest cooldown and has an AOE effect at level 1. Titan's Wraith isn't good enough at level 1 since it gets broken too fast by minion damage and the aoe effect/dot ends with the shield. second point into titan's wraith to jungle sustain. third point into riptide again to increase damage. fourth point into anchor for full combo (non-ultimate). you can grab the point in anchor earlier if you see an opportunity to gank a lane.

9/21/0 for Magic Penetration in Offensive tree and tanky regeneration in the defensive tree. This is for more damage output while staying as tanky as possible with sustain. You can also go 0/21/9 if you prefer the utility over Magic penetration.

Magic Penetration Marks really hurt early game as most people wouldn't expect that much damage from a tank and it also allows more damage throughout the whole game. Flat Armor Seals are standard for tank/jungle. Magic Resist per Level Glyphs for higher late game Magic Resist. AP Quints are what make your early game hurt. Landing even 1 skill can take a chunk out of the enemy's life.

The builds provided are only general guidelines to follow and should NOT be built in the exact order every game.

Regardless of what point of the game you are in, you should always buy wards. You should have bought at least 10 wards during a 40minute game. Every recall/death, try to get at least 1 ward if not 2. However, itemization is priority, unless you're support.

For laning, the doran ring really brings out the quality of the AP quints. It gives you health and more AP and mana regeneration. If you have a hard lane, you can go with boots and 3 red potions. Focus on last hitting but when you can sneak either a riptide to chip em down a little or scare them with an anchor. Harass sparingly if you can and save mana for when your jungler ganks. For jungling, cloth armor and 5 red potions are standard for jungling. After the starting items, get a philosopher's stone as soon as possible and also boots of speed. This is for taking advantage of the gold gain from philosopher's stone. Next you want to get heart of gold as soon as possible to also take advantage of the gold. After this, finish your mercury's treads. After this, build situationally. If you're taking too much magic damage, build some magic resist. If too much physical damage, build armor. If too much true damage, build health. If not taking too much damage and doing well and farming well, build some AP to completely dominate your role.

Item's in build
Mercury Treads- reduces CC, magic resist, movement,what else do you need? You can substitute this out for Ninja Tabi's if the opposing team has little or no cc and if they are AD heavy. You can also substitute treads out in low cc conditions with ionian boots of lucidity. The early CDR makes a big difference in whether they stay CC'ed for the kill or they get away with 20 health.

Shurelya's Reverie- mana regen, health regen, CDR and movement aura active. great on support's/tanks. use active to chase or escape

Aegis of the Legion- all around defenses makes you beefier and the defensive aura and slight AD boost really helps out the team. if you're a team player, best get this item.

Warmog's Armor- if you thought Nautilus was beefy naturally, after you get this, you go from being a bull to a mammoth. you get so much benefits from the high health and health regen. your w is your second most damaging skill when you're left to hit with your auto attacks and the shield scales off of health! more health=more time to auto attack-more DOT/AOE=OMG WHY TANK DO SO MUCH DAMAGE?!

Randuin's Omen- most standard armor item for full tanks since it builds from heart of gold. all the stats work well on nautilus and the AOE slow debuff active is godly in team fights. since you're most likely going to be initiating and going to be in the middle of team fights, this is an invaluable item to you and the team. the debuff can make or break teamfights.

Guardian's Angel- The overall defenses are good enough but DAMN. That insta-revive is great. You can safely initiate and if you die too quick, you come back quick to land your cc's anyway! If the timer is on for counting down the insta-revive and you feel the item isn't working as well, you can sell this and buy a different last item! don't feel that you HAVE TO keep it. And if you need it again for some reason and the timer is gone, rebuy it!

Item's to Consider
Rabadon's Deathcap- great last item for some ridiculous damage on a tank

Zhonya's Hourglass- doing well? wanted to stay tanky? BOOM, this is the item for you! you stay physically defensive while gaining some extra AP to bruise those enemy champions hard.

Rylai's Crystal Scepter- Just when Nautilus was hard to get away from in the first place, it becomes even harder. The slow from this procing on all your abilities is crazy. Extra AP? More damage. Extra health? More beef. aw yeah, that's the stuff.

Abyssal Scepter- great item to have if you find yourself in the middle of team fights and you have 2 or more other AP teammates. you'll be in the middle of the fight debuffing all the enemy champs while laying waste with your skills and your teammates take advantage of the same debuff and just leaves them crying.

Rod of Ages- only build this if doing well early and building it before heart of gold. this is a GREAT item on Nautilus, however, timing when to build it is hard. Build it too early and you gimp your early game. Build it too late and you won't get the full effects. Build it just right though gives you all the health/mana/AP you'll need to dominate mid-game into late-game.

Nautilus provides so much cc that he can't be ignored. It helps the team do what they need to do. Tanks initiate, take damage, peel enemies off your carries, and to protect your teammates. If you have to choose between letting a carry die or to save the carry and die yourself, save your carry!