I find most junglers have a more defined role of what they should be doing during team fights, with Nocturne being an execption. You can dive the carry with your ultimate, but you leave your team with out their bruiser and deep in the enemy line. On the other hand if you sit back and protect your carries you are subject to range damage and can't contribute that much damage of your own. So my question is what should Nocturne's focus be during team fights?
Nocturne is an assassin type jungler. He jumps on a squishy with his ult, keeps himself safe with his shield kill them and try flashing away. In the mid to late game (after laning phase), I see good nocturnes take the role of split pushing a little bit as his ultimate allows him to have better map presence than most champs, tf/pantheon/shen not withstanding, so he can force an enemy to stop his push and initiate a teamfight 4v5.