In a large bowl, combine diced cooked chicken with your choice of seasonings. Heat olive oil in a skillet over medium heat. Sauté chopped onion and minced garlic for about 1 minute until fragrant, then add chopped capsicum. Cook for an additional 2 minutes until tender.

Transfer skillet mixture to the bowl with chicken and stir to combine thoroughly. Allow cooling for about 5-10 minutes.

Preheat your oven to 220°C (430°F) or 200°C (390°F) for fan/convection setting.

Lightly oil a baking tray and place it in the preheating oven. On a tortilla, scoop a portion of the chicken filling, add a sprinkle of cheese, then fold the tortilla over the filling.

Remove the hot baking tray from the oven and place the assembled quesadillas on it. Bake for 8 minutes until golden. Flip using a spatula, press down, and return to the oven for another 8 minutes.

Remove from the oven and let them sit for a minute before slicing into wedges. Serve hot with salsa, guacamole, or salad.