Preheat the oven to 400°F (200°C).
Steam or microwave the chopped broccoli for 2 to 3 minutes until slightly tender. Drain well and let it cool.
In a mixing bowl, combine the broccoli, cream cheese, cheddar cheese, Parmesan cheese, minced garlic, parsley, and lemon juice until well mixed.
Cut a deep pocket into the side of each chicken breast without slicing all the way through.
Stuff each chicken breast with the broccoli mixture and secure the opening with toothpicks or kitchen twine.
Season both sides with garlic powder, onion powder, Italian seasoning, paprika, salt, and black pepper.
Heat the olive oil in an oven-safe skillet over medium-high heat.
Sear the stuffed chicken breasts for 3 to 4 minutes per side until golden brown.
Transfer the skillet to the oven and bake for 15 to 18 minutes, or until the chicken reaches an internal temperature of 165°F (74°C).
Let the chicken rest for 5 minutes before removing the toothpicks and serving.