You can Google "Restaurants near 24 W Randolph St, Chicago, IL" and see what is where in the area.
If you are looking for something that isn't a fast food chain, you can try:
Heaven On Seven
111 N Wabash Ave # 700, Chicago, IL
0.1 mi SE - (312) 263-6443
Trattoria #10
10 N Dearborn St, Chicago, IL
0.2 mi S - (312) 984-1718
Smith & Wollensky
318 N State St, Chicago, IL
0.2 mi N - (312) 670-9900
There are also several restaurants in Marshal Field's plus a food court on their lower level.
Note: Not all of the restaurants in the area of the theater show up on the search.