Begin by heating a skillet over medium heat. Add the two chicken breasts and cook for about 7-10 minutes, turning occasionally, until they are no longer pink in the center. Cover the skillet to keep them juicy. Once cooked, let them rest for a few minutes, then shred the chicken into bite-sized pieces.

In the same skillet, lower the heat slightly and warm the flour tortillas one at a time for about 10-15 seconds on each side to prevent tearing and make them more pliable.

On one half of each warmed tortilla, lay down a generous amount of shredded chicken, followed by the shredded cheddar and Monterey Jack cheese. Drizzle about a tablespoon of taco sauce over the cheese. Carefully fold the other half of the tortilla over the filling.

With a clean skillet over medium heat, add a tablespoon of vegetable oil, swirling to coat the bottom. Place the folded quesadilla into the skillet and cook for approximately 3-4 minutes until the bottom is golden brown.

Carefully use a spatula to flip the quesadilla and cook for another 3-4 minutes until the cheese is melted and the tortilla is golden brown.

Once fully cooked, remove the quesadilla from the skillet and let it rest for a minute. Cut it into wedges and serve hot with your choice of sides, like salsa or guacamole.