In the movie Batman is the actor who played young Jack Napier related to Jack Nicholson in any way?

There doesn't appear to be any connection between Hugo E. Blick and Jack Nicholson, but they do look a lot alike. Apparently, it was just a case of really good casting - finding a young actor that had the same kind of manic/cheeky grin that Nicholson. This is from an interview he did a while back:

"I was a writer working on a project at Pinewood. Legend has it that Nicholson saw me wondering the corridors. I do remember being called to meet Tim Burton where he had me say this weird line and grin."