Preheat oven to 350°. In a large bowl, combine the sour cream, half-and-half cream, onion, chiles, salt and pepper. Stir in the potatoes, chicken and 2 cups cheese. , Pour into a greased 13x9-in. baking dish. Bake, uncovered, until golden brown,1-1/4 hours. Sprinkle with remaining cheese before serving. If desired, sprinkle with chopped cilantro.