Chisora is one of those fighters that seems to do well in high profile fights but always seems to end up losing them all. I think the same would happen in this matchup.
Chisora pushes Valuev but still loses a wide decision. Derek, whilst decent, wasn't really world level good. And even tho Valuev is hardly an ATG, he'd still be the better fighter here, or at least the one most likely to win.