Whisk together cumin, paprika, oregano, garlic powder, salt, cayenne, and chilli powder in a small bowl.
After that, rub this spice mixture all over the chicken breasts.
Over medium heat, add 1 tablespoon of olive oil to a big skillet. Cook chicken in a skillet for 5–7 minutes on each side, or until golden and well done. When it is safe to handle, transfer to a cutting board, then dice and place in a medium bowl.
Add bell peppers and onions to the same pan that you used to cook the chicken (and extra olive oil, if necessary). To slightly soften, cook for 3 minutes. For the last minute of cooking, add the corn and black beans.
After that, clean out the skillet you've been using, or if you prefer, heat a griddle to medium heat. Each tortilla should have olive oil applied to one side.
In addition, put a tortilla on the skillet with the oil side up. Add some mozzarella shavings and about a half cup of the chicken mixture to the top. Add extra cheese and another tortilla, oil-side up, on top.
Cook for a further 2 to 3 minutes, or until the cheese is melted and the tortilla is crisp. The quesadilla can be turned over with a spatula and cooked for an additional minute, or until the second side is equally crispy. The tortilla can be pressed down with a spatula if it begins to curl up. Repeat with the rest of the cheese, chicken mixture, and tortillas.
On a cutting board, arrange the quesadillas and cut each one into quarters. Serve with salsa, avocado, cilantro, sour cream, and any additional toppings you like.