Preheat oven to 375?. Spray a 10-12 inch cast iron skillet or baking dish with nonstick spray. Set aside.In a medium bowl, stir together the softened cream cheese, Greek yogurt, BBQ sauce, onion powder, and garlic powder until smooth and combined. Add half of the cheddar and half of the monterey jack and stir. Add the shredded chicken and stir to combine.Add the chicken mixture to the skillet or baking dish. Top with remaining cheeses and bake for 25 minutes, or until cheese is bubbly and edges are golden.Once finished, sprinkle with red onion, cilantro, and scallions, and drizzle with extra BBQ sauce. Serve with tortilla chips or your favorite dippers!