"I really don't think I'm qualified to be running even a ward this small," Nicholas points out. "Surely you must have other staff?"

Nicholas wasn't so much implying that Guppy is unfit, so much as he was implying that he didn't seem like his head is really in the right place to be watching after Travis.

Which, as pissed off as he is at Travis right now, he does not want to see him get any worse.