Preheat oven to 375°F (190°C).
Lightly grease a 9x13-inch baking dish.
Heat olive oil in a skillet and sauté garlic for 30 seconds.
Stir in Alfredo sauce and heavy cream and heat gently.
Add Italian seasoning, salt, and black pepper.
In a large bowl, combine cooked pasta and diced chicken.
Pour sauce over pasta mixture and toss to coat evenly.
Transfer mixture to prepared baking dish.
Sprinkle mozzarella and Parmesan cheese evenly on top.
Bake for 20–25 minutes until cheese is melted and bubbly.
Garnish with chopped parsley before serving.