**Preheat Oven:**
Preheat your oven to 375°F (190°C).
**Assemble the Casserole:**
In a 9x13-inch casserole dish, combine the uncooked pasta, chicken, Alfredo sauce, chicken broth, milk, Parmesan cheese, garlic powder, salt, and pepper. Stir until all ingredients are evenly distributed.
**Top with Cheese:**
Sprinkle shredded mozzarella cheese evenly over the top.
**Cover and Bake:**
Cover the dish tightly with aluminum foil and bake in the preheated oven for 40 minutes.
**Check and Finish Baking:**
Remove the foil and stir the casserole gently to ensure even cooking. Return to the oven uncovered and bake for an additional 10-15 minutes, or until the pasta is tender and the top is golden and bubbly.
**Garnish and Serve:**
Let the casserole cool slightly before serving. Sprinkle with chopped parsley for a fresh touch.