Cook linguine according to package instructions until al dente. Drain and set aside.
In a large mixing bowl, combine the shredded chicken, cream of chicken soup, sour cream, melted butter, chicken broth, salt, pepper, and garlic powder. Stir in the cooked pasta until well coated.
Lightly grease a 9x13-inch baking dish. Transfer the pasta mixture to the prepared baking dish. Top evenly with mozzarella and Parmesan cheeses.
Bake covered for 30 minutes, then uncover and bake for an additional 10-15 minutes until the top is golden and bubbly.
Remove from oven and sprinkle with fresh chopped parsley. Let stand for 5 minutes before serving.