In a large bowl, combine the shredded chicken and BBQ sauce, mixing well until the chicken is fully coated.

In another bowl, mix the cheddar cheese, mozzarella cheese, garlic powder, onion powder, black pepper, and salt.

Heat a large skillet over medium heat and add 1/2 tablespoon of olive oil.

Place one tortilla in the skillet and sprinkle half of the cheese mixture evenly over the tortilla.

Spread half of the BBQ chicken mixture over the cheese, then top with the remaining cheese mixture.

Place a second tortilla on top and cook for about 3-4 minutes, or until the bottom tortilla is golden brown.

Carefully flip the quesadilla using a large spatula and add the remaining olive oil to the skillet. Cook for another 3-4 minutes until the second side is golden brown and the cheese is melted.

Remove from the skillet and let it cool for a minute before slicing into wedges.

Serve with sour cream and chopped green onions, if desired.