For the Filling:

1. Preheat Oven: Preheat your oven to 425°F (220°C).
2. Sauté Vegetables: Heat the olive oil in a large skillet over medium heat. Add the diced red bell pepper, jalapeños, and garlic. Sauté for about 3-4 minutes until the peppers are softened and the garlic is fragrant.
3. Add Remaining Filling Ingredients: Stir in the black beans, corn, and shredded rotisserie chicken.
4. Season: Sprinkle the mixture with chili powder, cumin, smoked paprika, salt, and pepper. Stir to combine and cook for another 2-3 minutes to allow the flavors to meld.
5. Set Aside: Remove the skillet from heat and set the filling aside.

For Assembly:

1. Prepare Baking Sheet: Line a baking sheet with parchment paper.
2. Layer Bottom Tortillas: Place 4 tortillas on the sheet pan, letting the edges of the tortillas hang slightly over the sides of the pan (these will fold over the top later).
3. Add Cheese: Sprinkle the shredded Monterey Jack cheese evenly over the tortillas.
4. Add Filling: Spread the filling mixture evenly on top of the cheese.
5. Top with Tortillas: Place the other 4 tortillas on top.
6. Brush with Butter: Brush the tops of the tortillas with melted butter.
7. Seal Quesadillas: Fold the overhanging edges of the bottom tortillas up and over the top tortillas to seal the quesadilla. Press gently to ensure everything stays in place.

Bake:

1. Press and Bake: Place another sheet of parchment paper and a pan or an oven-safe weight directly on top of the quesadillas to press them down while they bake. This ensures a crispy, evenly cooked quesadilla.
2. Bake: Bake for 20-25 minutes, or until the tortillas are golden brown and crispy.
3. Cut: Remove from the oven, and carefully cut the quesadillas into squares or wedges.

Serve:

1. Serve: Serve the sheet pan quesadillas warm, with optional toppings such as salsa, sour cream, fresh cilantro, diced red onion, or sliced jalapeños. Enjoy!