01 - Preheat oven to 375°F. Lightly grease a 9x13-inch baking dish.
02 - Cook the pasta in salted boiling water until al dente. Drain and set aside.
03 - Steam broccoli florets until just tender, about 3-4 minutes. Drain well.
04 - In a large bowl, combine cooked pasta, chicken, steamed broccoli, Alfredo sauce, milk, garlic powder, Italian herbs, and half of the mozzarella and Parmesan cheeses. Season with salt and pepper.
05 - Transfer the mixture to the prepared baking dish. Sprinkle the remaining mozzarella and Parmesan evenly over the top.
06 - Bake uncovered for 25-30 minutes, or until the top is golden and bubbly.
07 - Let rest for 5 minutes before serving.