Your budget and distance restrictions really limit you from a dining perspective. There are a ton of places I'd suggest that are > 1/2 mile away or cost > $20 a meal. That said, I'd recommend Xoco (Mexican) or Slurping Turtle (Japanese noodles).

If you look here you'll see that restaurants within 4 blocks of your hotel that are priced at $ or $$ consist primarily of chains. And you're staying in a more expensive, tourist-oriented neighborhood, so prices are higher across the board.

I don't eat Chicago pizza so I can't recommend any Chicago-style pizza places.

Sweet Willie's suggestion about the architectural cruise is spot on.