Preheat the oven to 375 degrees F (190 degrees C).
Melt butter in a large skillet over medium-high heat. Sauté garlic in butter for about 30 seconds.
Add prepared macaroni and cheese; cook, stirring occasionally, just until warmed through. Add in chicken, broccoli, mozzarella, ¼ cup Parmesan cheese, Italian seasoning, and pepper.
Transfer mixture into a greased dish. Top with panko and remaining Parmesan cheese.
Bake in the preheated oven until hot and bubbly, and panko is golden brown, about 20 minutes.
