Preheat your oven to 375°F (190°C). Lightly grease a baking dish large enough to hold the peppers upright.

Cut the tops off the bell peppers and remove the seeds and membranes. Rinse the peppers thoroughly and pat them dry with a paper towel.

In a large mixing bowl, combine the cooked chicken, cooked rice, pineapple chunks, and teriyaki sauce. Stir gently until all the ingredients are evenly coated in the sauce. Taste and adjust seasoning if needed.

Spoon the chicken and rice mixture into each prepared bell pepper, packing it tightly but not overfilling. Arrange the stuffed peppers upright in the baking dish.

Cover the baking dish loosely with aluminum foil to prevent the peppers from drying out. Bake in the preheated oven for 25–30 minutes, or until the peppers are tender but still hold their shape.

Remove the foil during the last 5–10 minutes of baking to allow the tops to caramelize slightly. Brush the tops with additional teriyaki sauce for a glossy finish and return to the oven for 2–3 minutes.

Remove the peppers from the oven and let them cool slightly before serving. Garnish with sesame seeds, chopped green onions, or cilantro for a pop of color and freshness.