
This creamy, cheesy casserole is so hearty and homey that second helpings are a must! —Lynne German, Woodland Hills, California
Cook spaghetti according to package directions. Meanwhile, in a large bowl, combine the chicken, soup, milk, onion, 1/2 cup cheddar cheese, 1/2 cup Swiss cheese, mushrooms, peppers, mayonnaise, steak seasoning and basil.
Drain spaghetti. Add to chicken mixture; toss to coat. Transfer to a greased 13x9-in. baking dish. Cover and bake at 350° for 20 minutes. Uncover; sprinkle with remaining cheeses. Bake until heated through and cheese is melted, 5-10 minutes longer.