Preheat the oven to 400°F (200°C) and line a rimmed baking sheet with parchment paper.
In a large mixing bowl, combine the ground chicken, Panko breadcrumbs, grated Parmesan cheese, minced garlic, beaten egg, parsley, milk, onion powder, salt, and pepper.
Mix the ingredients by hand until just incorporated, ensuring the seasonings are evenly distributed without overworking the meat.
Divide the mixture into four equal portions and shape each into an individual oval loaf approximately 1.5 inches thick.
Arrange the meatloaves on the prepared baking sheet, leaving at least 2 inches of space between each loaf.
Bake for 22 to 25 minutes, or until a meat thermometer inserted into the center of a loaf registers an internal temperature of 165°F (74°C).
Remove from the oven and allow the meatloaves to rest for 5 minutes before serving to retain juices.