Spray a 6 quart slow cooker with cooking spray. Line the bottom with half of the corn tortilla chips.
In a bowl, combine diced and cooked chicken, diced tomatoes with green chilies, cream of chicken soup, cream of mushroom soup, chicken broth and diced onions. Mix until combined.
Put half of the mixture over the tortilla chips and sprinkle half of the cheese on top. Repeat layers and end with cheese on top.
Cook on low for 4-6 hours and high for 3-4. Serve with additional tortilla chips if desired.