Don't play like an idiot. Try to all-in a good amount since you should usually win trades, especially bot lane with an enchanter supp buffing you and your W shield before going in with Q, your E has low cooldown and does good damage. At lvl 6 you become a monster and it becomes very hard to run away from you. You begin to 1 shot squishes and can do good vs tanks too. Be a bully. Get rich. Stomp.

You are still tanky from items built and do loads of damage and CC.

Nautilus is held back from being support where he doesn't get the gold he needs to shine, and doesn't build well. He builds as a lame tank, which holds him back.