Billy Goat and Mariano’s are pretty close, a 5 or 10 minute walk. Chipotle is even closer. For the others, I would recommend taking a short cab from the Pier to lunch and then another cab to the stadium.
Billy Goat is fun (the subterranean one below Michigan Avenue). They server diner burgers, not a culinary hotspot. I take out-of-towners there.
During the work week (closed weekends), one of my favorite cheap lunches is another below-ground venue, the Berghoff Cafe downstairs from the Berghoff restaurant. Same food, but served from a cafeteria line.
Monday – Friday 11AM to 2PM.
Miller’s Pub is another old-school place.
Again, not a gourmet place. It’s kind of a time machine to the 1950s.
Every day 11AM to 4AM
I know some people don’t want to visit a chain while traveling, but I like Chipotle and there is one very close to Navy Pier.
291 E. Ontario
Every day, 11AM to 10PM
Gold Coast Dogs 159 N. Wabash for a classic Chicago hot dog.
Call for hours they aren’t listed on the site.
There’s a great new grocery store near the Pier, Mariano’s Fresh Market They have a salad bar, sandwiches and I think sushi for eating in the store.
The 7th floor of Macy’s State Street (formerly Marshall Field’s) has a really good food court.
If cycling appeals to you, you can get a $7 24-hour Divvy bike pass, with unlimited 30-minute rides. If you keep a bike longer, you pay a few dollars.