Hi! This is my first build on mobafire.I play nocturne as a high attack damage/critical/movement speed build. I hope you enjoy it but please,try the build before voting...Trying the build before votting would mean before you go and say my build sucks...This build is more likely used in a 3v3 situation not a 5v5 match.But that doesn't mean its any worse, just different. Thank you and enjoy this build.

Doran's blade-good for lifesteal in early game for passive and for the extra health/dmg too.
Berserker's greaves-good for the attack speed that is needed to nocturne.
The black cleaver-excellent for nocturne because it has a lot of damage and it has even attack speed.
Infinity Edge-in my opinion,the best item in this game...for the critical and that damage it's the perfect item for nocturne.
The Bloodthirster- Life Steal and AD are excellent.. You probably won't die unless your ganked.. and it's awesome with nocturne's passive.
Phantom Dancer-it's the perfect item for each champion which is going on attack speed..so u can have extra movement speed and att speed.
Thornmail-you must sell doran's blade and buy thornmail..this item is for late game .. because u must resist .. and thornmail it's the perfect armor item for nocturne(in my opinion).

21-0-9 i think it's very offensive...but u need lvl 30 to have 30 masteries ...

I use Clarity and Flash . in the early game u must have clarity because u remain without mana ... or if u don't like clarity maybe use exhaust or ghost because they help u chasing the enemy or it can gives u an escape. Flash spell is good because u can surprise enemies or escape too.

Pros:
-Good Ganker
-Can make FB simple with him and very early
-Wonderful DPS
-Ult is excellent
-Passive with Lifesteal
-hard to counter...
-Great jungler
-Excellent Mobility
-Great Chaser/Pusher

Cons:
-Easily killed if not careful
-Long cooldown on ult(paranoia)
-if in the enemy team are tanks,u are fu*ked(especially in early game)

If you want a High AD/Movement Speed/Critical on noc try this build to make sure it's good(especially in 3v3).Now , sorry if i write something wrong!