Begin by preheating your oven to 375°F (190°C) and lining a baking sheet with parchment paper to prevent sticking.
In a large mixing bowl, combine the ground chicken, breadcrumbs, grated Parmesan cheese, chopped parsley, minced garlic, and finely diced onion.
Add the beaten egg, Worcestershire sauce, Italian seasoning, and a pinch of salt and pepper to the mixture. Gently mix everything together until just combined; take care not to overmix, as this could lead to a dense meatloaf.
Once combined, shape the mixture into a loaf form and place it on the prepared baking sheet.
Spoon the marinara sauce generously over the top of the meatloaf, ensuring it is evenly coated to keep it moist during baking.
Bake the meatloaf in the preheated oven for approximately 45-50 minutes or until a meat thermometer reads an internal temperature of 165°F (75°C).
Once cooked, remove the meatloaf from the oven and allow it to rest for 5-10 minutes before slicing to help retain its juices.
Notes
After slicing, garnish with freshly chopped parsley and serve with roasted vegetables or mashed potatoes.