Sauté vegetable in oil; add soups and Rotel tomatoes. Cook until blended. Layer in baking dish, tortillas, sauce, chicken, and cheese; repeat layers ... 40 minutes at 350°F.
Crush Dorito chips and place in large buttered casserole dish. Cook and debone chicken; spread over chips. Put onion over chicken, then Rotel tomatoes. Mix cream of chicken ... until brown and bubbly.