Heat oven to 350*F. Spray 9" x 13" glass baking dish with cooking spray. In medium bowl, mix chicken, Monterey Jack cheese, roasted peppers, chiles, and sour cream.
Spread about 2 tsp enchilada sauce on each tortilla. Top each with 1/2 cup chicken mixture. Roll up tortillas; arrange, seam side down, in baking dish. Top enchiladas with any remaining enchilada sauce. Sprinkle with Cheddar cheese. Spray sheet of foil with cooking spray; cover baking dish with foil, sprayed side down.
Bake 45 - 60 minutes or until thoroughly heated. If desired, remove foil during last 5 minutes of baking time. If desired, serve with lettuce, tomato, avocado, and additional sour cream.