Preheat the oven: Heat the oven to 375°F and lightly grease a baking dish if you are not using an oven-safe skillet.
Season the chicken: Pat the chicken breasts dry, then season both sides with garlic powder, Italian seasoning, salt, and black pepper.
Brown the chicken: Heat olive oil in a large skillet over medium-high heat and cook the chicken for about 2–3 minutes per side. The chicken does not need to be fully cooked yet.
Mix the sauce: Stir the Alfredo sauce and basil pesto together in a bowl until the pesto is evenly mixed through the sauce.
Arrange the broccoli: Place the broccoli florets around the browned chicken in the baking dish.
Add the Alfredo: Pour the Alfredo pesto sauce over the chicken and broccoli, making sure the chicken is well coated.
Add Parmesan: Sprinkle the grated Parmesan evenly over the top.
Bake: Cover the dish loosely with foil and bake for about 20–25 minutes, depending on the thickness of the chicken.
Check the chicken: Remove the foil and check the thickest part of the chicken with a food thermometer. It should reach 165°F before serving.
Rest and serve: Let the chicken rest for about 5 minutes, then spoon the creamy Alfredo sauce and broccoli over each serving.