So this is my first guide on the site, please excuse my non professionalism. If you liked the build feel free to hit the up vote button. also any comments on how I can improve would be much appreciated.

Now this guide is centered around fighting a very high AD team, if they have at least three AP champions this Build will not work. Maybe if enough people like this guide ill make a AP guide as well.

TABLE OF CONTENT
Runes
Masteries
Abilitys
Summoner Spells
Items
Jungling

Marks-So for marks iv chosen Greater mark of health, simply because in a tank build, between armor and health, the armor runes simply didn't provide enough defense to be worth the IP.

Seals-As far as seals go you get flat armor seals, it will give you that early game boost you need to survive jungle camps and go back to base less.

Glyphs-However for glyphs you want to go with scaling Runes of magic resist. Mages usually don't shine until mid to late game so you wont need as much magic resist early game. also as the build doesn't have any magic resist items, you will be relying solely on your natural stats, runes, and health to combat any mages on there team.

Quints-Now Nautilus is super slow, even with your boots you wont be running from any fight, if you get in a bad spot fight or die, that were your quints come in, between you boots and movement quints it should give you enough speed to escape some sticky situations.

For Masteries I go with 0/20/10

As a tank you don't need any damage your job is to simply catch, smash, and keep your teammates alive.

Naturally it feels like you should dump all you points into this titans defense tree, but early sustain can change the out come of a match. so you want just enough points in utility to get you biscuit skill, after that feel free to buff up your Defense as much as possible.

Titans Wrath-Start with your Titans Wrath skill, you'll need it, or the blue buff will mess you up, and you will end up consuming more biscuits then necessary.
Try not to active your shield until, all the jungle mobs in the camp are attacking you, it has a long cd and you don't want to wait a second of it.
Also its passive will allow you to clear camps with ease.

Riptide-On your first level up you want riptide, it will let you clear camps, quickly when paired with titans wrath.

Dredge line- you need this to start ganking, and one point at level 3 will fill those demands.

Depth Charge-as always, get your ultimate, and 6,11,16.

LEVELING ORDER
You want to level your shield and riptide evenly, it will provide sustain, damage and utility. leveling dredge line doesn't matter at all ,but at one point you sort of have to.

Flash-Its a good way to escape or set up a skill shot with your hook when ganking, its my personal presence.

Ghost-If you want to catch some one but your not a fan of flashes limited chase potential you want ghost, with all the movement utility iv included in this guide catching people shouldn't be a problem. I would honestly only get this if you don't own the movement quints.

Smite-I don't really need to explain this one, its a jungle guide, junglers use smite.

STARTER ITEMS
Hunters machete- the Hunter machete is a great starter item for most junglers, its will build into the essential items, and will disperse the jungle camps faster

Scrying Eye Orb- This item appears to be greatly over looked, However its ideal for nautilus. use the scying eye orb when ganking to set up your ultimate or your hook when those crafty champions are trying to escape through the bushes.

ESSENTAILS
Spirit of the ancient golem-this will provide great jungle sustain, gold, and armor, I suggest buying this item asap.

Giants belt-you need this item early because it will give you the health to be a little more reckless while ganking ;).

MOVEMENT OPTIONS
Boots of mobility-These boots just make me want to yell FOOTBALL, and tackle people with your giant anchor in hand and helps with roaming... these are especially useful if you are fighting people that are trying to back door a lot, and you need to put them in there place.

Ninja Tabi-If there adc is fed out the @$$, you may want to consider beefing up your defense just a tad more with these.

FINAL BUILD ITEMS
Frozen Mallet-The frozen mallet will allow you to stick to people like glue, while providing a sturdy defense, and the attack damage it provides is just frosting on the ice-cream cake.

Iceborn Gauntlet- if they thought they could run from you before all hope is gone now, plus the mana it provides will remove his mana issues.

Frozen Heart- A great item for some mid to late game tanking, it will alow you to jump right in on a team fight, and not really fear for your life, its passive will also force there ace to simmer down, and rethink there strategy.

Randuins Omen-Your already the god titan of ice, but why not bring it all together, this item will reinforcing frozen hearts passive, and providing, great chase and escape because its active effect.

NOTES
Upgrade to the farsight orb only if you have all your items, because its not really important to upgrade.
Between Spirit of the ancient golem, iceborn gauntlet, and frozen heart you actually achieve max cd reduction.

Always start with blue, you honestly don't even need red, but It gives Xp so its more of a I don't want some one else to take it.

I go blue, wolves, red. That should put you at level 3 and then you'll be ready to start ganking. after that, just balance killing jungle creeps, and ganking lanes.

Well thanks for giving my guide a read, and once again any advice to make, my guides more interesting or relatable, leave in the comments please and thank you, magga out.