It's not clear from your post, but it is important to note that the mall is but one part of Chinatown (the new part). That part runs down Archer (or thereabouts). Surprisingly, the mall has some of the more unusual offerings...if you are looking for a deer tail or real shark's fin, you're in luck.
There is an older part that runs down Wentworth. That's cool as well. People like Evergreen (and it's pretty good).
My new favorite is Lao Sze Chuan (mentioned above).
You might want to also check out Penang (where Wentworth and Cermak cross). I only mention this b/c it's Malaysian food. That's more difficult to come by.
Probably the best known restaurant in the mall is Lao Sze Chuan, at the western end (Szechuan, as you might guess). There's also Spring World, at the opposite end, which is Yunnanese, a new Taiwanese place, KS Seafood, Happy Chef, which is Cantonese, among other places. There's a bakery, St. Anna's, a branch of the Japanese candy store Aji Ichiban, which is fun to visit -- well, the whole mall is fun to visit.
Chinatown Mall is in an outside area. There are some expectional restuarants but that is not my area of expertiese so I will let others comment about that (I never really get to go there and when I do, my dad likes Joy Yee. However, I do know for a fact that there are many more better restaurnats than that).