This mastery is perfect. Don't judge.

take magic pen marks
armor seals
mr glyphs
Choose your own quints.

I myself prefer Health quints

He out sustain most solo top champs with catalyst.
He has all the CC to win trades.
He stomps enemy when being ganked in lane.
His W + passive = OP.

He stomps melee champs that has less CC or ability to kite like Irelia, Garen, Chogaht, Maokai, Yasuo and barely any champs that have to tank in front of you.

These are champs you might win against if you played well: Riven, Darius, Mundo, Zed, Warwick, and any champs with DPS skill.

These are champs you might want to avoid laning against: Jayce, Ryze, Lissandra, Kennen and most solo top ranged champs.

I had a lot of fun with him and I think he is one of the balanced champs :D

Core:

*Ward: Always have one ward with you if going counter jungling.

Catalyst: Winning ticket in your early game. You can spam ability really hard and win trades with your W. Evolve this into an awesome Rod of Ages.

Randuin's Omen: Helps you AA more. It works like your E.

Mercury treads: Helps you peel and dive. That is all.

Sunfire cape: Make your W more powerful. Deliver unexpected damage while your are around.

Banshee veil: Protects you from hard CC enemy team

Elixir: why not grab 250 extra HP :D

THIS IS ONLY WHEN YOUR TEAM NEED MORE DAMAGE..

Abyssal Scepter: In some cases that you need to be the one to KO the marked target, you probably need this if you don't have enough damage.

WHY NOT THESE ITEMS?.....

Rylai's Scepter: I agreed with its unique passive but your already had enough CC and you should go for stats upgrade. Forget the 100 AP you are playing the tank job.

Frozen Heart: You already had the omen. Late game mana cost isn't your problem.

Iceborn: YOu don't have AP to proc the passive

Iron locket: I rarely buy this instead of the banshee. It is a good pick to engage the fights, but I find it less rewarding because I still need banshee to dive.

Warmog/Thornmail/Righteous Glory: When extending to a super late game phase, people start getting full build, so you should sell your sunfire and start getting one of these. I prefer thornmail because I like to go verse the adc rather than protecting my adc. All of them are very useful for tanking and initiating.

I don't feel the need of maxing Q after W because of my play style. I'm more likely to keep the enemy close to me like collide them, walk with them and watch them burn and spam laugh.

The reason I take 2nd rank of Q at level 10 is because you wanna start roaming when you get the 2nd rank of the ultimate. The cool down was just perfect.

Remember! your combos can be improvise to adapt in many situations based on your opening because all of his ability are CC LOL. You can:
W > root > AA > E > AA > Q > AA > leave OR
W > E > root > couples AA > Q > AA > leave OR
E > W > root > couples AA > Q > AA > leave OR
Q > W > root > couples AA > E > AA > leave

You can activate your Randuin's Omen for extra root or AA too!!!!!!!

IF you do have your ultimate, after the AA you can R into your enemy face since it never missed and do the combo again XD. Why not 2X the combo!


Remember! Nautilus' potential relies on his W. If your W pops, you should back out.

The early game.
You have to survive early game and you are fine.
You should rush for catalyst because this is your winning ticket.
You can go agressive once you have upgrade the second rank of your W
You should use your W when engaging on last hitting to absorb the trade if they engage on you.
Then try use your E to slow them down and root them + one auto attack and walk away like a boss.
Your W gave you extra shield and damage that would make your enemy think again.

If this does not go very well, play passively! use W and E to last hit minions. Ask for gank once you have your Q ready because your CC will stomp them really hard or at least you could burn their flash.

What happen if you get ganked?
Nautilus won't die easily because you have all the CC to even counter them back. Or you can spam everything and run back to safety. And don't worry about your mana or losing farms, remember that you still have the teleport and I believe at this point you already picked up the catalyst. Once you picked that up you will find that Nautilus is fun :D

The mid game.
At this point you should be able to roam around with your Randuin's Omen and do some counter jungling with your W. >> take the gromp and put some ward around for your own protection.
You can travel anywhere for ganks when your jungler is busy because your ultimate was designed for this job. That is why he is meant to be in the jungle LOL.
You can turret dive as long as your W is active.

The team fights.
You should try to peel and root priority target because your R + W and mercury treads will allow your to do that. If you cannot peel due to some bad situations, you will want to try root the CC from enemy team. Or if thing has gone so bad you can just root anyone in front of you! trust me your passive is so good. It could turns the tides.

What happened if the enemy team has too much CC?
You probably would not ever do what I just guided above because you will still survive but your teammate will die.
Do your normal routine picking off the priority target with your ultimate. Do not dive for it as your teammate will do that for you. What you should do is try to clear path and counter the enemy CC.
Example:
You are against an enemy Nunu, once you mark your target with an ultimate. Your friend probably will try to participate. Save you Q or root if possible. Look for an opportunity to interrupt him from slowing your teammate.
It does not has to be a Nunu. Look for anyone that caused your team trouble getting in. Especially those who has constant CC you should interrupt them.
You can even root one enemy and turn to the other enemy interrupting him/her with your Q. Then E to apply CC on multiple enemies. PLEASE DO THIS FOR YOUR TEAM. Clear path and make sure your team don't get interrupted going for the target you marked with an ultimate.

The late game.
At this point, your W probably give you so much shield that you can sit on inhibitor turret. Anyone would avoid fighting you because your W and its damage would kill them unexpectedly. This is a time for you to do all the CC.

If you don't get counter from high threat level champs, that game will make your day.

Conclusion:
I still agree that Nautilus as a jungler is more effective.
Nautilus top is viable (well I should not say viable because any champs are).
His sustain is so OP and his W will threaten your opponent's life.
He is good at roaming and counter jungling as a solo top even if you are losing your lane.
He 100 percent REKT Irelia.

Have fun with him :) but I still recommend taking him to the jungle lel.

Cinderhulk is not possible with top lane Nautilus not only that I lose my teleport for smite but I have no use of it when I keep minion waves closer to my turret. I don't need the clear speed like a jungler Nautilus would do.

Added Abyssal Scepter to the build.

Making custom matches to lane against new Ryze to see if he is now winable.