Nocturne

Nocturne seems like a very powerful jungler due to his ganking. His chasing is imba with Q (movement speed + attack damage), E (fear) and mostly R (blink over half of the map). He can also heal himself with his passive. And that's all a jungler wants.

Here's a little video on his jungling.

His ultimate mechanics are new to LoL.
"Nocturne reduces the sight radius of all enemy champions and removes their ally vision in the process. He can then launch himself at a nearby enemy champion."
Now this can be verry annoying. Especially when playing solow - when you aren't on any kind of voip with your teammates. He ultis and you have no idea what's going on on the map. You can only expect something like "Nocturne has slain an ally" withing next seconds. You never know who he will attack and who you should help survive. That ulti is mainly the reason he is considered somewhat OP and is very often banned in competitive games. In premades this ulti is not as strong as it is in solo queue due to voice chat, but still it can be a real pain in the ass. 


He can also solo lane if needed. He can actually be strong solo laner due to his heal and Q as harass. Also it help to have him 6 soon so he can gank easily. But jungle just seems like more popular choice for him. 


Overall Nocturne is pretty strong, maybe a little bit OP champion. We'll see what they'll do to him in the upcomming patch.