Preheat the oven to 425°F (220°C). Spray a quarter sheet pan with nonstick spray and set aside.
In a medium mixing bowl, combine the shredded chicken, drained corn, drained and rinsed black beans, chili powder, cumin, garlic powder, smoked paprika, and kosher salt. Stir until evenly mixed.
Arrange 4 of the tortillas on the sheet pan so each one has half hanging off the edge. Divide the chicken mixture evenly among them, spreading it to cover the tortilla centers.
Sprinkle the shredded Mexican blend cheese evenly over the chicken mixture on each tortilla.
Fold the remaining 4 tortillas over the filled ones to create quesadillas. Place a second sheet pan or another heavy oven-safe pan on top to press them flat and keep them together.
Bake with the top pan in place for 20 minutes. Carefully remove the top pan, then bake the quesadillas uncovered for an additional 10–15 minutes, until the tortillas are crisp and the cheese is melted.
Remove from the oven and transfer to a cutting board. Cut into squares or triangles and serve warm topped with guacamole, sour cream, and salsa as desired.