I like chili served over macaroni, so a pot of that wouldn't be uncalled for (and would help stretch the chili, too). Actually, I like corn stirred into my tomato-based chili, too. And sour cream. And cheese. (but you've already got those 2 on your list)
Veggie tray would be a good choice, and not too hard to put together.
How about a simple green salad? Then people can pour chili onto it to make taco salad.