Preheat oven to 350°F (175°C).
In a large mixing bowl, combine the softened cream cheese, cheddar cheese, Monterey Jack cheese, buffalo wing sauce, ranch dressing (and blue cheese dressing, if using), green onions, and garlic powder. Mix well.
Add the shredded chicken to the bowl. Gently fold the chicken into the cheese mixture until evenly distributed.
Transfer the mixture to your prepared baking dish. Spread it out evenly.
Bake uncovered for 20-25 minutes, or until bubbly and golden brown.
Optional: Broil for the last 1-2 minutes to get a nice browned top. Watch carefully.
Remove from the oven and let cool slightly before serving.
Garnish with additional green onions or a drizzle of buffalo wing sauce, if desired. Serve warm with your favorite dippers.