01 - Preheat oven to 425°F. Line two baking sheets with parchment paper.
02 - In a large bowl, toss shredded chicken with chili powder, cumin, garlic powder, salt, and black pepper until well combined.
03 - Lay 4 tortillas flat on work surface. Evenly distribute chicken mixture, cheese, bell pepper, and green onions over each tortilla, leaving 1/2-inch border around edges. Top with remaining tortillas and press gently to seal.
04 - Brush both sides of each quesadilla with melted butter or olive oil.
05 - Place quesadillas on prepared baking sheets. Bake for 8-10 minutes, flip, and bake another 7-8 minutes until golden and crisp.
06 - Let cool 2 minutes, then cut into wedges. Serve warm with salsa, sour cream, or guacamole if desired.