Nautilus can be one of the best tanks in the game if played correctly. I max dredge line first to get assist for the lane you are in. If you are lanning with a carry, then dredge line is the best to get as you rope them in, your carry hits, then as nautilus's passive it slows and reduces armor. Hopefully your team will score first blood. Also mid game, nautilus will be a very strong tank and the best initiator for your team.