1Heat oven to 350° F. Spray 13x9-inch (3-quart) glass baking dish with cooking spray. Pour 1/2 cup of the salsa in baking dish.
2In large bowl, stir together chicken, beans, corn, sour cream and 1 cup of the cheese. Spoon about 2/3 cup filling onto center of each tortilla. Fold bottom third of tortilla over filling; fold in sides toward center, leaving top open. Place burritos, seam sides down, on salsa in baking dish. Spoon remaining 1 cup salsa over filled burritos. Sprinkle with remaining 1 cup cheese.
3Bake uncovered 20 minutes or until cheese is browned and melted. Garnish with onions.