Nicholson did a perfect job as the regular joker as the Batman/Detective Comics one. But Tales of the Dark Knight is a much darker version. It is basically the version that Bob Kane really wanted but thought it would be way too dark for mainstream comics. Back in the day it wouldn't have worked out.
Now Bale's batman is really the way Batman was supposed to be, no sidekicks ever! Also this Joker is completely insane. I mean if you think Nicholson's Joker was insane, this one is worse. Also Christopher Nolan has already said that as long as he is directing Bale there will no Robin ever.