Preheat oven to 350°.
Place oven bag in a 13- x 9-inch baking dish. Add flour to oven bag; twist end of bag, and shake.
Drain 1 can tomatoes. Add tomatoes and remaining undrained can tomatoes to bag; squeeze to blend ingredients. Add beans and next 3 ingredients to bag. Arrange ingredients in an even layer.
Close oven bag with nylon tie; cut 6 (1/2-inch) slits in top of bag.
Bake at 350° for 40 minutes. Sprinkle with cheese, and serve over tortilla chips. Garnish, if desired.