In a large bowl, combine the shredded chicken, crumbled bacon, cheddar cheese, mozzarella cheese, ranch dressing, garlic powder, onion powder, salt, and pepper. Mix until well combined.
Heat a large skillet over medium heat and add the olive oil.
Place one tortilla in the skillet and spread about 1/4 of the chicken mixture evenly over half of the tortilla.
Fold the tortilla in half and cook for about 3-4 minutes, or until the bottom is golden brown and the cheese is melted.
Carefully flip the quesadilla and cook for an additional 3-4 minutes on the other side.
Remove from the skillet and let it cool for a minute before slicing into wedges.
Repeat steps 3-6 for the remaining tortillas and filling.
Serve warm, garnished with fresh cilantro if desired.