Combine the seasoning ingredients in a small bowl and set aside.
Heat olive oil in a large skillet over medium-high heat then add the onion and peppers. Cook for 4-5 minutes until softened. Add the garlic and cook for 1 minute, stirring frequently to avoid burning. Add the shredded chicken, black beans, and 1 tablespoon of the Mexican seasoning blend and stir until combined. Cook for around 2 minutes then remove from heat and transfer mixture to a plate.
Wipe the pan clean and return to the heat. Reduce heat to medium. Brush one side of a tortilla with melted butter, then set the tortilla in the pan with the buttered side down.
Top the whole tortilla with a small handful of each of the cheeses. Add approximately ⅙ of the chicken and vegetable mixture on one half of the tortilla and cook for around 1-2 minutes.
Fold the cheese side of the tortilla over the side with the chicken mixture and cook for another minute until the cheese is melted and the tortilla is lightly browned. If the tortilla starts to brown too much, flip to the other side to finish cooking.
Repeat the process with the remaining tortillas, then cut into wedges and serve.