Preheat your oven to 350°F (175°C).
Cut the tops off the bell peppers and remove the seeds and membranes. Place them upright in a baking dish.
In a mixing bowl, combine the shredded chicken, buffalo sauce, softened cream cheese, cheddar cheese, green onions, garlic powder, onion powder, salt, and pepper. Mix until well combined.
Spoon the buffalo chicken mixture into each bell pepper, packing it tightly and mounding it slightly at the top.
Top each stuffed pepper with additional shredded cheddar cheese.
Cover the baking dish with aluminum foil and bake in the preheated oven for 20 minutes.
Remove the foil and bake for an additional 5 minutes, or until the cheese on top is bubbly and slightly golden.
Let the stuffed peppers cool for a few minutes before serving. Drizzle with extra buffalo sauce if desired.