Remember, Nick is irrational. Trying to reason with him is pointless. Instead, acknowledge where you may "fall short" and what you intend to do about it -- work harder, work smarter, work under closer supervision, whatever.
Then ask if he had to choose between someone who meets his exacting requirements and someone who can willingly do the job and better, who would he pick and why? Be ready to make your case. Nick doesn't do callbacks.