Preheat the oven to 375°F (190°C).
In a large skillet, heat the olive oil over medium heat. Add the ground chicken and cook until browned, about 5-7 minutes.
Stir in the garlic powder, ginger powder, salt, and pepper. Cook for another minute until fragrant.
Add the cooked rice, pineapple chunks, and teriyaki sauce to the skillet. Mix well and cook for an additional 2-3 minutes until heated through.
While the filling is cooking, cut the tops off the bell peppers and remove the seeds and membranes.
Place the bell peppers upright in a baking dish. Spoon the chicken and rice mixture into each pepper, packing it down slightly.
Top each stuffed pepper with shredded mozzarella cheese.
Cover the baking dish with aluminum foil and bake for 25 minutes. Remove the foil and bake for an additional 10 minutes, or until the cheese is bubbly and golden.
Remove from the oven and let cool for a few minutes. Garnish with chopped green onions if desired before serving.