Well, this is the first build I've actually put on any build site for any game, but I figured I'd give it a shot. My Nautilus build I feel is a sort of up-in-the-enemies'-faces build that allows even an amateur tank player to feel like a boss by running into a group and Lol-ing (pun very intended) at them run. I basically build Nautilus as tanky as necessary to get the job of initiating done, but still have a little fun in the process because he's tough as Hell to kill with his medium damage and huge crowd controlling.

I give Nautilus these runes not only to give him a quick edge to harass early game with the armor and magic resist, but to also keep the enemy on their toes when they let me get close enough to land a shot of armor pen + Staggering Blow on them. The gold per 10 quints allow for constant gold generation, even if it is at a rate of 3 per 10 sec, but you'd be surprised at the difference that little bit makes with Philosopher's and Heart of Gold the whole game.

For my masteries, I go 0/21/9 to make myself as tanky as I can early on and give me the movement speed from utility to chase down retreating enemies for my carries, even under turrets (but that's for later on *evil laughter*). If you want to jungle Nautilus, I don't know what to say; I don't personally enjoy it so I don't do it.

My items are aimed at giving me very fast gold generation early on in order to keep "my farm up" in a sense. This means that even if you're having a bum start to a game, you can still acquire your items through gold generation and the occasional jungle mob if you keep getting harassed. Keep yourself out of dodge until you get a few items and you'll be set. One alternative to the build ( I haven't tried it but if you want to go for it) may be to swap our your Ninja Tabi for Mercury Treads and turn your Philosopher's Stone into a Shurelya's if you find yourself against more ability power than just physical damage/"auto attackers."

As brief as it is, I hope that this build lets you get a somewhat decent grasp on Nautilus so that eventually you'll be able to make your own build for him how you like! Now get out there and smash some anchors to your enemies!!!