Preheat oven to 375°F and grease a 9x13-inch baking dish liberally with softened butter. Set aside.

Cook pasta in salted boiling water for 1 minute less than the package directions. Drain and set aside.

In a large bowl, whisk together cream of chicken soup, cream cheese, garlic, sour cream, chicken broth, parsley, garlic powder, black pepper, and salt to taste.

Stir in half of the mozzarella and cheddar cheeses, then add the shredded chicken and cooked pasta. Mix well.

Transfer mixture to the prepared baking dish and top with remaining cheeses.

Bake uncovered until the casserole is bubbly and the top is golden brown, 30–35 minutes.