Preheat oven to 400°F (200°C). Grease a baking dish.
Toss potatoes with olive oil, salt, pepper, and paprika. Spread them in the baking dish.
Add diced chicken on top and pour the Parmesan garlic sauce mixed with water or stock.
Sprinkle shredded mozzarella cheese evenly over the dish.
Cover with foil and bake for 25 minutes.
Remove foil, add grated Parmesan (if using), and bake uncovered for another 10 minutes until golden and bubbly.
Garnish with fresh parsley and let it rest for 5 minutes before serving.
Enjoy warm with your favorite sides!