Preheat the oven to 400°F and line a baking sheet with parchment paper.
Combine the chicken, bacon, mozzarella, cheddar, ranch dressing, garlic powder, onion powder, and black pepper in a large bowl.
Warm the flour tortillas for 15 to 20 seconds under a damp paper towel so they are flexible.
Place about one-third cup of filling on one side of each tortilla, fold over, and press gently.
Arrange the tacos on the baking sheet and lightly brush or spray both sides with olive oil or melted butter.
Bake for 8 to 9 minutes, flip carefully, and bake for another 6 to 8 minutes until golden and crisp.
Broil for 1 to 2 minutes if desired, watching closely to prevent burning.
Rest for 2 minutes, then serve with lettuce, tomatoes, green onions, and ranch dressing.