PREHEAT oven to 350°F. Grease 11- by 7-inch baking dish.
SPREAD 1/2 cup enchilada sauce on bottom of prepared baking dish. Combine chicken, 1/2 cup enchilada sauce, 1/2 cup cheese and chiles in medium bowl. Spoon chicken mixture evenly down center of each tortilla; roll up. Place seam-side down in baking dish. Top with remaining enchilada sauce and cheese.
BAKE 15 to 20 minutes or until heated through and cheese is melted.
Top with sour cream and chives, if desired.