Add the ground chicken, breadcrumbs, sliced green onions, low-sodium soy sauce, egg, garlic powder, salt, and pepper to a large bowl.
Thoroughly combine the ingredients in the bowl to form the meatball mixture.
Use a 1-tablespoon cookie scoop to portion out 20-24 meatballs. Gently roll each portion into a ball and place them on a baking sheet lined with parchment paper.
Bake the meatballs at 400°F for 15-18 minutes, or until the meatballs are fully cooked and reach an internal temperature of 165°F.
While the meatballs bake, make the pineapple teriyaki sauce. Peel and grate the fresh ginger. In a saucepan, combine the crushed pineapple, low-sodium soy sauce, honey, and grated fresh ginger.
Use an immersion blender to puree the sauce directly in the saucepan, or blend the mixture in a blender or food processor until smooth. Then, heat the sauce over medium-low heat until warmed through.
Add the cooked meatballs to the sauce and toss to coat, or pour the sauce over the meatballs before serving.