Preheat your oven to 375°F.
In a large skillet, heat the olive oil over medium heat. Add the minced garlic and sauté for about 1 minute until fragrant.
Stir in the broccoli florets and cook for another 3-4 minutes until they are bright green and slightly tender.
In a large mixing bowl, combine the cooked chicken, sautéed broccoli, heavy cream, mozzarella cheese, Parmesan cheese, Italian seasoning, salt, black pepper, and red pepper flakes. Mix until well combined.
Transfer the mixture to a greased 9x13 inch baking dish, spreading it evenly.
Bake in the preheated oven for 25-30 minutes, or until the top is golden and bubbly.
Remove from the oven and let it cool for 5 minutes before serving.