Preheat oven to 350°.
Combine 1/2 cup salsa and sour cream in a small bowl, and spread evenly over each tortilla. Divide chicken, tomato, bell pepper, and onion evenly down center of each tortilla, and roll up. Place rolls, seam sides down, in an 11 x 7-inch baking dish coated with cooking spray. Top with 1/2 cup salsa. Bake at 350° for 15 minutes. Sprinkle with cheese; bake an additional 5 minutes or until cheese melts.