Preheat oven to 350. Line a 9 x 13 pan with aluminum foil with the dull side toward the food. Combine chicken, soup, ½ cup sour cream and ¾ cup cheese. Spoon about ¼ cup of the chicken mixture down center of each tortilla and roll up. Place seam-side down in foil-lined baking dish. Top with salsa and remaining ¾ cup cheese. Cover with foil, dull side toward food. Bake 15 minutes. Remove foil. Continue baking 10 minutes longer or until cheese is melted. Top with remaining sour cream, if desired.