Mix ground chicken with eggs, onion, breadcrumbs, half the basil, Parmesan, garlic and salt until just combined. Divide in half and form into 2 free-form "loaves"; each about 6 x 3.5 in. (15 x 9 cm). Place both on large foil-lined baking sheet.
Spread each loaf with tomato sauce. Bake in oven preheated to 400°F(200°C) for 45 min. Sprinkle each loaf with mozzarella and continue to bake another 5 to 7 min. or until cheese is melted and meat thermometer inserted in centre registers 165°F (74°C).
Garnish with remaining basil. Serve with more heated tomato sauce, if desired, as accompaniment to spaghetti.
These meatloaves are just as delicious made with ground turkey, beef or pork. Serve one loaf for dinner and save the other for leftovers during the week, including cold in sandwiches.