Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper if desired.
In a mixing bowl, combine the ground chicken, breadcrumbs, chopped green onions, grated pineapple, minced garlic, minced ginger, egg, salt, and black pepper. Mix until well combined.
Shape the mixture into meatballs, about 1.5 inches in diameter, and place them on the prepared baking sheet.
Bake the meatballs in the preheated oven for about 15 minutes or until they are cooked through and golden brown.
While the meatballs are baking, heat a frying pan over medium heat. Add the teriyaki sauce and pineapple chunks, and bring to a simmer.
Once the meatballs are done baking, transfer them to the frying pan with the teriyaki sauce. Toss them gently until well coated in the sauce. Cook for an additional 3-5 minutes to heat everything through.
Serve the meatballs garnished with sesame seeds and additional chopped green onions.