Nautilus is a safe pick in almost every situation in champion select. No matter what composition your team cooks up Nautilus will most likely fit in pretty well and in my opinion I think he is one of the best champions to first pick as well.

Pros:
- Tank
- Tons of Crowd Control
- Amazing Peel
- Good for early team invades
- Amazing for catching out enemies
- Amazing Teamfighter
- Good early damage (for trading as support)
- Good jungle sustain

Cons:
- Low damage
- Big hit box
- Slow movement speed
- Slow attack speed
- Hook can't go over walls

Jungle First Clear:

Gromp Smite -->
Blue Sentinel -->
Murk Wolves -->
Red Brambleback Smite -->
Krugs -->
Recall

Why to use Smite on Gromp and Red Brambleback (Red Buff).

Smiting Gromp will you give you a buff called "Gift of the Toadstool" and it will last for 90 seconds. This buff applies poison to anything that attacks you. This helps you clear camps and helps with killing enemy champions.

Smiting the Red Brambleback will give you 20% of your maximum health back to help you stay in the jungle and continue clearing.

Personally I think every ADC is good with Nautilus, you just sometimes need to change your playstyle. Nautilus provides amazing peel and is tanky which is great for every ADC.

Here are some of my favorite Bot Lane duos:

Nautilus & Graves
- These two can blow up enemy champions instantly in lane giving the enemy no reaction time with Nautilus's CC and Graves's Burst.

Nautilus & Vayne
- This Duo scales extremely well into late-game and is unstoppable in team fights.

Nautilus & Jinx
- There is a lot of kill pressure with this duo as Jinx's Flame Chompers! gives more CC to stack on top of Nautilus's CC. Jinx also scales very well and can do her thing while not having to worry about getting blown up or dived by enemy champions.

Nautilus & Sivir
- Because skins get wins! Sivir's On The Hunt provides even better engage for Nautilus. You won't be able to get away from these two nor will you be able to catch them. Sivir's Spell Shield makes Sivir an even safer pick when paired with Nautilus.

--Apart from ADCs/Marksmen, here are some other champions that Nautilus is good with.--

Nautilus isn't just good with marksmen, but he is also good with some other champions as well. One of those champions is Yasuo as Nautilus can use Depth Charge and Dredge Line to make targets ultable for Yasuo.

Nautilus also does really well with Blitzcrank or Thresh because who doesn't like to chain hooks? This would obviously mean that Nautilus would not be playing support when along side with Blitzcrank or Thresh.

Nautilus has a lot of peel so this makes him good with any other immobile/long range damage dealer such as Zyra, Xerath, Kog'Maw, Azir, Malzahar, Orianna, Ziggs etc..

Stalker's Blade actually kinda funny on Nautilus, it provides even more CC for a CC packed champion. This is the jungle item I prefer because it usually guarantees kills from ganks. The move speed steal is very nice and helps Nautilus's slow move speed when chasing somebody down early in the game.

Ranger's Trailblazer is the item I recommend to new Nautilus players as it greatly increases jungle clear speed and makes it so you spend less time in the jungle and more time on the map.

Enchantment: Cinderhulk is the enchantment you always want to go for when jungling Nautilus. The +15% Bonus Health is a must-have on tank junglers in this meta. It also makes Nautilus pretty tanky early game and scales very well throughout the game. It also provides you with free damage-over-time in combat dealing damage to nearby enemies. This gives Nautilus good damage and clear speed.

Relic Shield/ Face of the Mountain provides you with a good gold income and sustain in lane as support Nautilus. Later in the game when you upgrade into Face of the Mountain you get a nice shield which you can place on any of your teammates. This item is far better than any of the other support items for Nautilus. It is best for you to not upgrade this item and you will find yourself not getting as many stacks off as the game goes on and the shield isn't that good later in the game.

Warmog's Armor is an item I only build on Jungle Nautilus. The reason for this is so you can take a huge advantage from the bonus +25% Health from Enchantment: Cinderhulk. Other than that, Warmog's Armor isn't very good on Support Nautilus and the gold could be spent for efficiently somewhere else.

Spirit Visage is an item that you would rarely build. The only case I would personally build Spirit Visage is in a situation where I had both Enchantment: Cinderhulk and Warmog's Armor and the enemy team was heavily magic damage based. Even then I would probably build Locket of the Iron Solari and Banshee's Veil before thinking about Spirit Visage. Spirit Visage would be good if your team had a Soraka or just a lot of healing in general.

Frozen Heart is also another situational rare build item like Spirit Visage. The only times I would build Frozen Heart is when the enemy team had at least two attack speed/attack damage based champions. Like Master Yi, Jinx, Vayne, Fiora, Caitlyn, Nocturne, Twitch, etc.. It works best on support and top Nautilus.

When jungling as Nautilus, always take Smite and Flash.

When supporting as Nautilus, you can choose from Ignite, Exhaust, or Teleport always with Flash.

[VERY RISKY] Only use Teleport for a roaming style Nautilus. I highly recommend Mobility Boots with this style of Nautilus.

However, always use Teleport on top lane Nautilus as it helps you and your team create a lot of map pressure.

Dredge Line

RANGE: 1100 COST: 60 / 70 / 80 / 90 / 100 MANA COOLDOWN: 18 / 16 / 14 / 12 / 10

ACTIVE: Nautilus hurls his anchor forward in a line. If it hits an enemy unit, Nautilus drags himself and the unit together, dealing magic damage and briefly stunning the enemy.
Dealing scaling magic damage. MAGIC DAMAGE: 60 / 105 / 150 / 195 / 240 (+ 75% AP)

If the Dredge Line hits terrain, Nautilus will drag himself forward and the cooldown is reduced by 50%.

=Tips & Tricks=
-When Dredge Line hits a target it will pull both you and your target to eachother and Nautilus will automatically start basic attacking that target. This will guarantee a root with Staggering Blow.
-When Nautilus kills a target with dredge line it will pull Nautilus the full distance instead of half way.
-When Nautilus lands a hook on terrain, he will pull himself to the left side of the anchor. (Video on this below)

How to use Nautilus's Dredge Line Effectively on Terrain

Play Video

Titan's Wrath

COST: 80 MANA COOLDOWN: 18

ACTIVE: Nautilus gains a shield for up to 10 seconds that absorbs a base amount of damage plus a percentage of his maximum health. SHIELD STRENGTH: 65 / 70 / 75 / 80 / 85 (+ 9 / 11 / 13 / 15 / 17% of max health)
While the shield persists, Nautilus's basic attacks apply a debuff to all enemies within 175 range of his target, dealing bonus magic damage over 2 seconds. MAGIC DAMAGE: 30 / 40 / 50 / 60 / 70 (+ 40% AP)

=Tips & Tricks=
-This ability is an auto attack reset.
-Watch your shield because if you lose it you will lose the bonus AOE magic damage.

Riptide

RANGE: 600 COST: 40 / 50 / 60 / 70 / 80 MANA COOLDOWN: 7 / 6.5 / 6 / 5.5 / 5

ACTIVE: Nautilus slams the ground, causing a ring of explosions to radiate out from him in 3 waves. Each explosion deals magic damage to enemies in the area and slows them, decaying over 1.5 seconds.
MAGIC DAMAGE PER WAVE: 60 / 95 / 130 / 165 / 200 (+ 30% AP)
SLOW: 30 / 35 / 40 / 45 / 50%
MAXIMUM MAGIC DAMAGE: 120 / 190 / 260 / 330 / 400 (+ 60% AP)

=Tips & Tricks=
-Enemies take 50% less damage from explosions beyond the first that hits them.
-This ability is absolutely amazing in teamfights as it is a huge AOE slow on a very low cooldown.
-Enemies who run away from Nautilus will most likely get hit by all three waves of Riptide.

Depth Charge

RANGE: 825 COST: 100 MANA COOLDOWN: 140 / 110 / 80

ACTIVE: Nautilus fires a shockwave that chases a target enemy champion, dealing magic damage and knocking up enemies it passes through for 0.5 seconds. The shockwave explodes upon reaching its target, dealing magic damage to the target, as well as knocking them up for 1 second and stunning them.
PASSTHROUGH MAGIC DAMAGE: 125 / 175 / 225 (+ 40% AP)
EXPLOSION MAGIC DAMAGE: 200 / 325 / 450 (+ 80% AP)
STUN DURATION: 1 / 1.5 / 2

=Tips & Tricks=
-Try and position yourself so that Depth Charge will travel through as many enemies as possible so you can knock them all up.
-Be aware that this ability can knock enemy champions over small walls if they are nearby the targeted champion. (Ex: Nautilus uses R on enemy Katarina, there is also an enemy Yasuo between Katarina and a small wall. Yasuo will get knocked over the small wall if he is close enough to it and still within range of Depth Charge's explosion.

Staggering Blow

Nautilus's Basic Attacks deal bonus physical damage and root his target for 0.5 / 0.75 / 1 / 1.25 / 1.5 seconds.

This ability can only be used on the same target every 9/8/7/6 seconds

=Tips & Tricks=
-When Dredge Line hits a target it will pull both you and your target to eachother and Nautilus will automatically start basic attacking that target. This will guarantee a root with Staggering Blow.
-This ability is great for peeling teammates as it is a free root.