Heat oven to 350 degrees and spray 13x9 inch (3 quart) glass baking dish with cooking spray. In large bowl mix soup, sour cream and milk until blended.Add chicken, tortillas (tore into bite size pieces). Stir in salsa and 1 cup of cheese Mix well until all is coated.
Spoon and spread mixture in prepared baking dish and crush white corn chips over casserole until covered. Cover with aluminum foil and bake for 40 minutes. Uncover sprinkle with remaining cheese (1/2 cup or more to taste). Bake uncoverd for 5 to 10 min until cheese is melted and mixture is bubbly. Let stand for 5 minutes.
Serve with additional sour cream and salsa as desired. Refried beans go well with this as well. You can also serve the remaining tortilla chips with this as well