Cook onion and red bell pepper in butter until tender, about 5 minutes. Stir in salt and chili powder.
In a large bowl combine soup, onion mixture, milk and 2 cups cheddar cheese and parmesan cheese. Mix well. Stir in chicken, pasta and green chiles.
Spread into a 9x13 casserole dish. Top with remaining cheese.
(Nutrition information provided is an estimate and will vary based on cooking methods and brands of ingredients used.)