Preheat oven to 350°F.
In a large bowl, combine ranch dressing, cream cheese, and hot sauce until smooth.
Stir in chicken, 1/2 cup mozzarella, 1/2 cup cheddar, and most of the green onions.
Spread into a baking dish.
Top with remaining cheese.
Bake until bubbly, approximately 20 minutes.
Sprinkle with blue cheese and the remaining green onions.