Cube potatoes and put in a large pot full of cold water. Bring to a boil and cook until tender, about 15 minutes. Drain. Return potatoes to pot, mash with butter or margarine. Stir in milk and sour cream. Season to taste with salt, pepper and garlic powder.
Divide mashed potatoes into individual servings in bowls. Divide the corn on top of the potatoes. Add a layer of hot chicken “things” on top of the corn. (see this post for reheating instructions if you are using them from frozen.)
Melt 2 T. butter or margarine in a saucepan. Stir in 2 T. flour and cook for 2-3 minutes, stirring often. Whisk in chicken stock, bring to a boil and simmer until thickened. Stir in salt and pepper to taste
Spoon some gravy over the chicken in each bowl and add some shredded cheese, if desired.