Preheat your oven to 375°F (190°C).
Prepare the bell peppers by cutting the tops off and removing the seeds.
In a large bowl, combine shredded chicken, Buffalo sauce, cream cheese, garlic powder, onion powder, and half of the shredded cheese.
Season the mixture with salt and pepper, adjusting to your taste.
Stuff each bell pepper with the Buffalo chicken mixture.
Place the stuffed peppers in a baking dish and top with the remaining cheese.
Cover the 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 brown.
Let the stuffed peppers cool for a few minutes before serving, and garnish with chopped green onions if desired.
