Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
So now you may ask: why Nautilus? then I say that he have one of the best jungler kit in the game to date with his q whihc is a good gap closer and acts as a stun, his w wich gives you AoE damge and a big shield, his e which is a good slow with big range and also does a decent amount of damage and then his r which is a "global ult" that knocks up everything in the way of the projectile.
Pros / Cons
-good and fast jungle clear
-early ganks can start at lvl 3
-q is a good gap closer
-q and passive makes for good "stuns" e slows and mixed with frozen mallet they have almost no escapes
-w makes for a good shield and gives you quite a bit of AoE damge
-e and q makes for good escapes
-not too good late game
-you have quite low tankyness in the early game before you have rod of ages or warmogs
-you almost do no damge and therefore need the adc/mid laner to engage with you