Preheat the oven to 375°F (190°C). Lightly grease a 9-by-13-inch baking dish.
Cut the chicken into approximately 1-inch pieces. Divide the broccoli into bite-sized florets.
Steam the broccoli for 3–4 minutes until bright green and slightly tender. Drain thoroughly.
Season the chicken with garlic powder, paprika, Italian seasoning, salt, and black pepper.
Heat olive oil in a large skillet over medium heat. Brown the chicken for approximately 4–6 minutes, working in batches if necessary. Transfer to a plate.
Reduce the heat to medium-low. Melt the butter in the same skillet and cook the minced garlic for 30–45 seconds until fragrant.
Add the softened cream cheese and heavy cream. Whisk gently until smooth.
Gradually add the Parmesan, black pepper, and Italian seasoning. Simmer gently for 2–3 minutes until creamy.
Return the chicken to the skillet and add the drained broccoli. Stir until everything is coated in the sauce.
Transfer the mixture to the prepared baking dish and spread evenly.
Sprinkle the mozzarella and remaining Parmesan over the top.
Cover loosely with foil and bake for 15 minutes. Remove the foil and bake for another 10–15 minutes, until the cheese is melted and the chicken reaches 165°F (74°C).
Rest for 5 minutes, garnish with fresh parsley, and serve warm.