Sauté chicken, Fiesta Party Dip Mix and onions in olive oil until chicken is no longer pink. Add green chilies. Sprinkle cheese evenly on 4 tortillas. Top cheese with equal amounts of chicken mixture; top with second tortilla. Brush outsides of tortillas with vegetable oil. Heat grill or griddle to medium heat. Grill quesadillas for 2-3 minutes on each side or until lightly browned and cheese melts. Cut into wedges; garnish with sour cream and Corn, Black Bean Salsa. Makes 8-10 servings.