preheat oven to 350°. in a large skilled, cook beef and onion over medium heat till meat is no longer pink. add garlic and cook one minute longer. drain fat from meat. stir in beans, tacos sauce, tomatoes, chilies, and olives. bring to a boil. reduce heat; simmer uncovered for 20-25 minutes or till slightly thickened.

in a large casserole dish layer burrito halves, meat, and cheese, making two layers.

cover and bake at 350° for 20 minutes. uncover and bake an additional 10-15 minutes longer or till bubbly and cheese is melted.