Nick
I think the last episode where Nick did the best mentoring he could ever do! He stepped away and let the team work. If you don't remember, Tim Gunn does this all the time on PR. He lets them make their own noose to hang by or the team works it out and creates something winning!
Nick needs to remember that he's not the teacher in this situation. When teaching, you can take the reins and the students can learn, whereas with mentoring, he needs to trust. I think his team was expecting him to not back them up and they created something that they could defend without his help.
I know that I would rather be proud of my work on my own rather than use my mentor as a crutch and the creativity.