Cook spaghetti according to package directions. Meanwhile, in a bowl, combine the chicken, 1 cup cheese, soup, milk, pimientos if desired, salt and pepper. Drain spaghetti; add to the chicken mixture and toss to coat.
Transfer to a greased 13-in. x 9-in. baking dish. Sprinkle with the remaining cheese. Bake, uncovered, at 350° for 20-25 minutes or until heated through. Yield: 6-8 servings.