Preheat oven to 375°F (190°C).
In a large skillet, heat olive oil over medium heat and sauté garlic until fragrant.
Add heavy cream and cream cheese, stirring until smooth.
Stir in Parmesan cheese and season with salt and pepper.
In a large bowl, combine cooked chicken, steamed broccoli, and sauce.
Transfer mixture to a greased 9x13-inch baking dish.
Top with shredded mozzarella cheese.
Bake for 20-25 minutes, or until bubbly and golden brown on top.
Serve hot.