Hi there. This special build for nocturne is different from any other builds. This require you to be a glass cannon in the game which makes you vulnerable to focuses. This is why you don't participate in team fights. Your job is to assassinate anyone who is wandering around by themselves. This build also provides great opportunity to split push enemy lanes(unknown embed type)

When you have to do the job of a jungler :(, ganking with nocturne isn't that hard. The best time to gank is at level 6 when you have your ultimate, but i can teach you how to gank at level 3. You want to land your q on the enemy laner then use your e. The e will cause them to fear and walk slow. Make sure you have your stalker's blade before you gank. If your team is doing fine then don't gank and keep farming. You can solo dragon once you have your phantom dancer.

If you are forced to teamfight make sure you're not tanking anything. Stay in the back and play like an assassin. Once you enter your teamfight try to use your q on most of the enemy players. Use your e on the carry. Once they are feared burst them down with your remaining crit. Time your w properly and block and cc.

When your split pushing make sure the enemy team is distracted. If they catch you use your q to slither away. If any ashe arrow is coming to you use your w to stop it.
When you're dueling make sure you have your w ready to go. It is important for you to win the duel with your w. And remember to always have your q on the enemy champ your dueling.
With the core build you have the ability do even out duel a pantheon or a gangplank

Don't be the hero and try to kill everyone when you don't have your team with you lol. Avoid champs with blinding skills like teemo and if your w is down don't try to duel anyone.