Nocturne is my favorite champion right now. I have more then 200 battle with him and feel like this build is what works best for me.

These are the runes that I use when I play Nocturne. This set up gives you 11.4% extra attack damage and 3.4% attack speed. It also gives you survivability in the jungle with armor and magic resists and it helps when ganking lanes.

The items I chose for nocturne were focusing on damage output and some what on defensive stats. . This build has a lot of damage and enough tank item so you can dive the enemy's back line and destroy their carry and survive. . This build is for when your team needs a tank and your the only one that can build tanky but I don't personally like it as much as other builds.