Preheat oven to 350 degrees. Grease a 9x9" square baking pan.
Mix Cheese Whiz, soup, milk, chiles and onion together in a 2 quart sauce pan. Cook until melted together. Add chicken. Stir until mixed together. Add any seasonings you like: salt, pepper, garlic powder, etc.
Crush half the taco shells and place in the bottom of the 9x9 pan. Pour in chicken mixture. Crush the rest of the taco shells and place on top of the chicken mixture.
Bake in oven for approximately 35 minutes or until bubbly. Serve and enjoy.