Preheat oven to 450°F.
In a bowl, mix together ground beef, salt, pepper, garlic powder, and onion powder. Roll into balls and place on a baking sheet. Bake for 10 minutes.
While meatballs bake, heat oil in a large pan over medium-high heat on the stove top. Add minced garlic and yellow onion, sauté for 2-3 minutes.
Stir in brown sugar, rice vinegar, soy sauce (or tamari), cup ketchup, apple cider vinegar, chili sauce, and 1 ½ cups pineapple juice (reserve ¼ cup). Bring to a boil.
In a small bowl, whisk together remaining ¼ cup pineapple juice and cornstarch until smooth. Slowly pour into the boiling sauce while continuing to whisk. Let it thicken for 1-2 minutes.
Reduce heat to simmer. Add baked meatballs and chopped green bell pepper and red bell pepper. Simmer for 5 minutes.
Stir in fresh pineapple chunks. Taste and adjust seasonings if needed. Serve over rice and garnish with green onions. Store any leftovers in an airtight container.
