Preheat the oven.

In a large bowl, combine ground chicken, egg, breadcrumbs, Parmesan cheese, garlic, parsley, onion powder, paprika, salt, and pepper.

Form the mixture into bite-sized meatballs.

In a saucepan, melt butter and whisk in the flour to create a roux.

Gradually add milk, stirring constantly until the sauce thickens.

Stir in grated Parmesan, mozzarella, nutmeg, salt, and pepper to the sauce.

Place meatballs in a baking dish and cover them with the cheese sauce.

Bake in the oven until cooked through and golden brown.

Serve with mashed potatoes or cauliflower purée and garnish with fresh thyme or parsley, drizzling with olive oil or butter if desired.