I need a nautilus build that is good. What do I do?

Google 'Nautilus build,' find one for the role you want to play him in, then read the entire thing. For example...

http://www.mobafire.com/league-of-le...e-guide-186131

Don't forget that these guides aren't shining examples of perfection. Modifying item builds, rune slots, or summoner abilities to fit your tastes is always encouraged.

whatever makes you unstoppable

edit
lol @ mobafire

well.. in my opion naut wouldnt be a viable jungler so... i guess you could use him as an ap. try like.. a few dorans rings and go from there. Dont bother with ROA cus tt games are usually 15-25mins. and by the time you get it, it most likely wont be full by the end.