Combine first 5 ingredients and half the cheese; mix well. Blend in sour cream, onion and pepper; set aside.
Arrange half the tortillas over the bottom of a greased 13"x9" baking pan. Spoon half the chicken mixture over tortillas. Repeat layers, ending with chicken mixture on top. Sprinkle with remaining cheese; top with olives.
Cover loosely with aluminum foil; bake at 350° for 40 minutes or until hot and bubbly.