Preheat oven to 400°. Brown beef in a skillet on the stove. While beef browns, chop pepper and onion.
Add all ingredients but the cheese to a 9x13 casserole dish and mix well. Bake for 40 minutes, then remove foil and top with cheese. Bake again for an another 2-3 minutes, until cheese is melted.
Serve with sour cream and tortilla chips. Keep leftovers in fridge up to one week.