Place chicken breasts in a saucepan with about 3 cups of water. Cook chicken breasts until no longer pink in the middle. Remove from pan and allow to cool. Chop chicken into small cubes and put aside. In a large Saucepan, melt butter and cook onion until soft, about 5 minutes
Add chicken broth to onions and bring to a boil. Add hash brown potatoes and cook over low heat for approximately 20-25 minutes or until potatoes are soft, but not mushy. Stir occasionally.
Stir in corn, cubed chicken and green chiles and return to a boil. Disolve gravy mix in the milk and stir into the boiling mixture. Cut up the cheese into cubes and add to the chowder mixture. Turn stove down to medium low and stir constantly until cheese has melted.
This chowder improves flavor wise every day! Enjoy!