There is good theater, but not right now....
Big shows are all gone - no more Wicked, Lion King, etc. There are a bunch of revivals here and there for 2-4 weeks runs like Cats, Sister Act, etc. Jersey Boys is back for a short time. Opera season is over.
Not much until fall. Try
Broadway In Chicago Show and Theatre Tickets
Might be some smaller shows at northern theaters -
http://www.chicagoplays.com