Preheat your oven to 375°F.
In a large mixing bowl, combine the ground chicken, breadcrumbs, Parmesan cheese, milk, parsley, onion, garlic, egg, salt, black pepper, Italian seasoning, and red pepper flakes. Mix until all ingredients are well combined.
Transfer the mixture to a loaf pan and shape it into a loaf.
Spread the marinara sauce evenly over the top of the meatloaf.
Bake in the preheated oven for 45-55 minutes, or until the internal temperature reaches 165°F.
Let the meatloaf rest for 10 minutes before slicing.
Serve warm with your favorite sides, such as mashed potatoes or steamed vegetables.