01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper or lightly grease it.
02 - In a large bowl, combine the ground chicken, breadcrumbs, egg, green onions, garlic, soy sauce, ginger, black pepper, and salt. Mix gently until just combined, being careful not to overwork the mixture.
03 - Roll the mixture into 1-inch meatballs and arrange them on the prepared baking sheet, spacing them evenly.
04 - Bake for 18-20 minutes until the meatballs are cooked through and lightly golden on the outside.
05 - While the meatballs bake, combine the pineapple juice, soy sauce, rice vinegar, brown sugar, and ketchup in a saucepan over medium heat. Bring the mixture to a simmer, stirring occasionally.
06 - In a small bowl, dissolve the cornstarch in the water. Slowly whisk the slurry into the simmering sauce and cook for 2-3 minutes, stirring constantly, until the sauce thickens and becomes glossy.
07 - Stir the drained pineapple chunks into the thickened sauce and simmer for an additional 2 minutes to warm through.
08 - Transfer the baked meatballs into the saucepan, tossing gently to coat each meatball evenly. Cook together for 2-3 minutes until everything is heated through. Serve hot, garnished with fresh cilantro or parsley, over steamed rice or noodles.