Preheat your oven to 375°F. While it heats, halve your bell peppers lengthwise and carefully remove all seeds and white membranes. Lightly grease a 9x13 inch baking dish (or similar size to fit your pepper halves snugly) and arrange the pepper halves cut-side up in the dish. Pour about 1/4 inch of water into the bottom of the dish—this will steam the peppers gently as they bake and keep them tender.

In a medium saucepan over low heat, combine the hot sauce, melted butter, salt, garlic powder, and onion powder. Warm gently for 1-2 minutes, stirring occasionally, until the flavors meld together—the butter should be fully incorporated and the mixture fragrant. Add the shredded chicken and stir well to coat thoroughly in the buffalo sauce. I like to use rotisserie chicken here because it's already perfectly cooked and shreds easily, which keeps the filling tender rather than dry.

Remove the saucepan from heat and stir in the Greek yogurt until completely combined with the chicken mixture—the yogurt will cool the filling slightly and add a creamy tang that balances the heat beautifully. Fold in 1 cup of provolone cheese and the black pepper, mixing gently until the cheese is evenly distributed throughout. The provolone will soften as you mix it in and help bind the filling together.

Divide the buffalo chicken filling evenly among the prepared pepper halves, mounding it generously in each cavity. The filling will cook down slightly during baking, so don't be shy with the amount. Place the baking dish in your preheated 375°F oven and bake for 30-35 minutes, until the pepper halves are tender when pierced with a fork and the filling is heated through. I like to check them around the 28-minute mark so I can gauge how soft the peppers are getting.

Remove the baking dish from the oven and let it cool for 2-3 minutes so you can handle it safely. Scatter the crumbled feta cheese evenly over the top of each filled pepper half, then garnish generously with sliced green onions. The warm peppers will slightly soften the feta while keeping it distinct and creamy, creating a nice contrast with the spicy buffalo filling.