In a large mixing bowl, combine the cooked chicken breast, shredded cheese, ranch dressing, diced green onions, diced bell pepper, and black pepper. Mix well until all ingredients are evenly distributed and coated in ranch dressing.

Heat a non-stick pan over medium heat and add a tablespoon of olive oil. Swirl the oil around the pan to ensure it coats the bottom evenly.

Place a flour tortilla into the preheated pan, letting it warm for about 30 seconds. Spoon a quarter of the chicken mixture onto one half of the tortilla, spreading it evenly. Carefully fold the tortilla over the filling, creating a half-moon shape.

Sear the quesadilla for 3-4 minutes until the bottom is golden brown and crispy. Flip the quesadilla and cook for an additional 2-3 minutes.

Remove the cooked quesadilla from the pan and let it rest for about 2 minutes on a cutting board. Use a sharp knife to cut the quesadilla into wedges.

Serve your Easy High-Protein Chicken Ranch Quesadilla hot, optionally with extra ranch dressing on the side for dipping.