Preheat the oven to 375°F. In a medium bowl, mix the cream cheese with a rubber spatula until very creamy and smooth. Mix in the buffalo sauce and ranch dressing. Stir in the chicken, blue cheese, 1 cup of cheddar cheese, and one-half of the scallions. Transfer to a 1.5 quart casserole dish, such as an 11-inch-by-7-inch casserole dish. Top with the remaining cheddar cheese. Bake for 18-20 minutes, until the edges are bubbly and the cheese is melted on top. Remove from the oven and let rest for 5 minutes. Sprinkle with the remaining sliced scallions. Serve with veggies and chips.