Been a long time since I was in Chicago, but I really liked:
Al’s for an Italian beef. White Castle for a couple of burgers (only have em frozen in Maryland – it’s a short walk from Midway). Lou Malnati’s for deep dish pizza. Billy Goat for one cheezborger cheezborger (not that great, but I’m a nostalgia/SNL chump). Portillo’s for a Chicago style hot dog (no sport peppers, I’m a panty-waist).
I know it’s a short trip fpr you, but if you have time, the Field Museum is excellent.