Preheat oven to 425 degrees Fahrenheit (218 degrees Celsius).
In a small bowl, toss shredded chicken with 1/4 cup of the buffalo sauce until evenly coated.
Place flatbreads on a large baking sheet.
Spread the remaining buffalo sauce evenly over the surface of the flatbreads.
Top with shredded mozzarella cheese, followed by the buffalo chicken and red onion.
Bake for 10 to 12 minutes or until the cheese is melted and the crust edges are golden brown.
Remove from oven and sprinkle with blue cheese crumbles.
Drizzle with ranch dressing and garnish with chopped chives before serving.