Preheat the oven to 400°F (200°C).
In a medium bowl, combine the shredded chicken and buffalo sauce. Mix until the chicken is well coated.
Place the flatbread on a baking sheet. Brush each piece lightly with olive oil and season with salt and pepper.
Evenly distribute the buffalo chicken mixture over the flatbreads.
Sprinkle the shredded mozzarella cheese and blue cheese crumbles on top of the chicken.
Bake in the preheated oven for 12-15 minutes, or until the cheese is melted and bubbly.
Remove from the oven and drizzle ranch dressing over the top. Garnish with chopped green onions.
Slice into pieces and serve hot.