Heat over medium high until the cheese is melted and all of the ingredients are mixed together well. Begin by heating the oven to 350 degrees so it can preheat while you assemble the casserole. In a large mixing bowl combine the diced chicken chunks, cream of chicken soup, canned chilis, sour cream, diced onions, milk, garlic salt, salt, and pepper. Grease a 9×13 casserole dish. Preheat oven to 350 degrees F (175 degrees C). Slice tortillas into 1-inch strips. Whisk to combine well. Spray the 9 x 13 inch baking dish with non stick cooking spray. Set aside for a few minutes. Step 2 In a 5 quart pot combine the chicken, cream of celery soup, cream of chicken soup, enchilada sauce, diced tomatoes and green chiles, onion, garlic, chicken broth, chili powder and cheese. Mix onion, salsa verde, cans of soup, milk, garlic powder, and pepper in a bowl.