Preheat oven to 375°F (190°C). Lightly grease a baking dish.
In a large bowl, mix cooked chicken, rice, pineapple tidbits, teriyaki sauce, and half of the shredded cheese until well combined.
Arrange bell pepper halves cut-side up in the baking dish. Spoon the filling evenly into each pepper.
Sprinkle the remaining cheese on top of each stuffed pepper.
Cover the dish with foil and bake for 30 minutes until peppers are tender.
Remove foil and broil for 2–3 minutes until the cheese is melted and lightly golden.
Garnish with sliced green onions and serve warm.