01 - Preheat oven to 425°F and line two baking sheets with parchment paper.
02 - Combine shredded chicken with chili powder, cumin, garlic powder, salt, and black pepper in a large bowl. Toss until evenly coated.
03 - Place 4 tortillas on work surface. Distribute seasoned chicken, cheese, bell pepper, and green onions evenly over each, leaving 1/2-inch border. 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 carefully, and bake additional 7-8 minutes until golden brown and crispy.
06 - Let cool for 2 minutes before cutting into wedges. Serve warm with salsa, sour cream, or guacamole if desired.