Re: have nothing on somebody
As I read it, it would be similar to the idiom "he couldn't hold a candle to him." I think you know that one already, don't you?
A had nothing on B (in this context) means that B is far superior to A.
(When I first saw the subject line, I thought it was going to mean that they had no evidence to support a suspicion that someone had done seomthing wrong. As in "We can't hold him any longer. I think he did it, be we have nothing on him. We need more evidence to make an arrest.")
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.