In a small bowl, combine the chopped broccoli, mozzarella cheese, cream cheese, garlic powder, onion powder, salt, and pepper. Mix until well blended.
Carefully cut a pocket in each chicken breast by slicing horizontally, ensuring not to cut all the way through.
Stuff each chicken breast with the broccoli and cheese mixture, securing the opening with toothpicks if needed.
Heat olive oil in a large oven-safe skillet over medium heat. Sear the stuffed chicken breasts for 2-3 minutes on each side until golden brown.
Transfer the skillet to the preheated oven and bake for 20-25 minutes, or until the chicken is fully cooked and the internal temperature reaches 165°F (75°C).
Remove from the oven, let the chicken rest for a few minutes, then serve. Enjoy your broccoli stuffed chicken!