Preheat the oven to 425°F (220°C). Line a large baking sheet with parchment paper or lightly grease it.

In a bowl, toss the chicken pieces with olive oil, garlic powder, onion powder, paprika, salt, and black pepper until evenly coated.

Spread the chicken on the prepared baking sheet in a single layer and bake for 15 to 18 minutes, stirring once halfway through, until cooked through and lightly crispy on the edges.

In a small bowl, mix the melted butter with the 1/2 teaspoon garlic powder. Brush one side of each tortilla lightly with the garlic butter.

Flip the tortillas over and place them on the baking sheet, buttered side down. On one half of each tortilla, layer a little cheddar, mozzarella, baked chicken, chopped bacon, and a drizzle of ranch dressing.

Sprinkle the remaining cheese over the filling, then fold each tortilla in half to form a taco shape.

Bake the folded tacos for 6 to 8 minutes, flipping carefully once if needed, until the tortillas are golden and crispy and the cheese is melted.

Remove from the oven and let cool for 1 to 2 minutes. Top with green onions if using, and serve with sour cream or shredded lettuce if desired.