In a skillet, saute onion and green pepper in butter until tender. Remove from the heat. Stir in the soup, mushrooms, pimientos and basil; set aside. In a large bowl, combine noodles, chicken and cheeses; add mushroom sauce and mix well. Transfer to a greased 13x9x2 baking dish. Bake, uncovered, at 350~ for 40 to 45 minutes or until bubbly. Sprinkle with crumbs. Bake 15 minutes longer.
