Buono Beef is one of my long-time favorites for an Italian beef. I haven't been to the location on Superior, but I used to make the one in Berwyn my regular Saturday lunch place. If you are coming to Chicago for any period of time, you must have at least one Italian beef sandwich, preferably dipped and with hot giardinara.
I work in the area where you will be doing your residency. While I don't get out for lunch that often, here are some of the places I go with my coworkers for lunch. Or would like to if I could find the time. I do not have the exact addresses (sorry), so I will give you the general vicinity, and you should be able to find them easily enough. I would recommend any of them as a nearby place with good food.
Bandera - a rotisserie restaurant on Michigan avenue (east side) near Illinois St. I favor the lamb sandwich and the big salads. Not at the same sitting, as the portions are very generous.
Dao Thai - on Ohio east of Michigan avenue. It offers very decent Thai food at reasonable prices, something rare for the Gold Coast/Streeterville area.
Luxe Cafe - on Michigan Avenue, second floor of Omni Hotel. I haven't been there yet, but have it on my list.
Emilio's - Tapas place on Ohio St, again east of Michigan Avenue, near Columbus.
And I will finally admit, I am a sucker for Big Bowl for pan-Asian food. There is one on Rush Street and one on Ohio, west of Michigan avenue. Love the homemade gingerale and kung pao noodles. Not Chinatown, but I still like it and it is close.