In a large bowl, combine the cream of chicken soup, sour cream, Parmesan, poppy seeds, parsley, garlic powder, and black pepper. Stir, then add the cooked chicken and stir again until the meat is evenly coated in sauce. Transfer to a 9x13-inch baking dish.
5 cups cooked chicken, 2 cans cream of chicken soup, 16 ounces sour cream, 3/4 cup freshly grated Parmesan cheese, 1 Tablespoon poppy seeds, 1 Tablespoon dried parsley, 3/4 teaspoon garlic powder, 1/2 teaspoon black pepper