Preheat the oven to 350°F/180°C.
Prep the peppers, slice them in half, and remove the membrane and the seeds.
Place on a baking tray or in a casserole dish, drizzle with olive oil and brush it all over the peppers. Season with salt and pepper. Cook in the oven until they’re just undercooked, about 10 minutes.
As the peppers are being roasted, prepare the filling. In a large bowl, combine the shredded chicken with buffalo sauce, ranch dressing, mozzarella cheese, garlic powder, and onion powder. Stir to combine.
Remove the peppers from the oven, and carefully fill them with the prepared filling. Return to the oven and cook for 5 more minutes, then place under the broiler for 1-2 minutes.
Remove from the oven, and top with crumbled blue cheese and/or ranch dressing, and sliced green onions.