Brown ground chuck in skillet over medium high heat, drain fat and set aside. Add 1/2 cup water and taco seasoning to skillet and mix well. Return to heat and allow to simmer while mixing other ingredients.
In a large bowl, mix cream of chicken soup, Rotel tomatoes, and sour cream together. Stir in bell peppers, green chilies, onion, and 2 cups of cheese, mixing well. Fold in hashbrown potatoes and set aside.
Coat the inside of a Dutch oven or 13x9 generously with shortening or spray. Place half the hashbrown mixture evenly in bottom of oven, add ground chuck and top with remaining hashbrown mixture.
Cook in 375 degree oven for 30 minutes. Add rest of cheese and cook 15 more minutes or until bubbly.