A quick description
Clairvoyance: So very useful on Noc, never have to rely on your team mates line of sight to use your ult. Amazing for ganking enemy junglers as well, and their team doesn't even know who's being attacked until it's too late.
Exhaust: Great for reducing damage in head on fights and also preventing escapes after ulting.
Nocturne is a strong harasser early game, and can often get first blood due to his ability to chase ppl down with his Q + exhaust. You can start jungling around level 4-5 if you wish to let your team mate farm xp tho.
This guide is meant to give you survival and excellent damage output and tank killing capabilities. I have over 50 games with Nocturne already, and this has become my standard build.
This guide provides excellent survivability endgame, with lots of armor, good amount of magic resist, extra HP, good life steal, spell blockage, and insane damage and armor pen. Pop Ghostblade and Randuin's (if you ever get it) right after you land on someone with your ultimate.
Standard Build is:
1) AS Boots
2) Bloodrazor - please note that once you get your full bloodrazor, you should be able to 1v1 any champion on the field.
after this you can fill your last 2 slots according to who you're playing against.
if DPS heavy, get Thornmail and/or Bloodthirster
if Caster Heavy get Banshee's and/or Guardian Angel and/or Trinity Force
if Tank heavy get Black Cleaver.
Put your Ghostblade in 1 slot, and Randuins in 2 slot, get in the habit of popping these immediately after you activate your ult and engage the team.
Why no IE?
Infinity Edge is an item I do not recommend on Noc.. I see alot of noc's use it, but to be quite frank, I completely destroy those noc's 1v1, and their survival is really low in team fights compared to this build. This build has at least 200 armor, and I often am still alive at the end of team fights, despite being focused.