In a large bowl, combine the mashed potatoes, egg, flour, chives, garlic powder, salt, and black pepper. Gently fold in the cheese.
2 cups mashed potatoes, 1 egg, 1/2 cup all purpose flour, 2 tablespoons chives, 1/2 teaspoon garlic powder, 1/2 teaspoon kosher salt, 1/8 teaspoon black pepper, 1 cup cheese