Preheat your oven to 375°F (190°C). Grease a 9x13-inch baking dish with olive oil.

In a large mixing bowl, combine the chicken breasts, zucchini, cherry tomatoes, red onion, and garlic. Drizzle with olive oil, then add oregano, basil, paprika, salt, pepper, and optional red pepper flakes. Toss everything together.

Spread the mixture evenly in the prepared baking dish, ensuring the chicken pieces are nestled among the vegetables.

Sprinkle the mozzarella and Parmesan cheese over the top of the mixture.

Cover with aluminum foil and bake for 20 minutes.

Remove the foil and continue baking for an additional 10-15 minutes, until the cheese is bubbling and golden, and the chicken is cooked through.

Let the dish rest for about 5 minutes before serving. Garnish with freshly chopped parsley.