Make the filling: In a medium bowl, combine shredded chicken, buffalo sauce, and cream cheese. Stir thoroughly until the cream cheese is fully incorporated and the chicken is evenly coated. Taste and add a little more buffalo sauce if you want increased heat.
Preheat your skillet: Heat a nonstick skillet or cast-iron pan over medium heat. Add a small amount (½ tsp) of butter or olive oil and swirl to coat the pan.
Assemble the quesadilla (one at a time): Place one keto tortilla in the pan. Sprinkle a light, even layer of shredded cheese over the entire tortilla (this helps seal the filling). Spread ~½ cup of the buffalo chicken mixture evenly on top of the cheese, leaving a thin border around the edge. Sprinkle the green onions on top, then add another light layer of cheese. Top with a second tortilla.
Cook first side: Cook for 3–4 minutes until the bottom tortilla is golden brown and the cheese is beginning to melt. Use a wide spatula to press gently so the quesadilla holds together.
Flip carefully: Flip the quesadilla and cook the other side 3–4 minutes until golden and the cheese is fully melted. If the tortilla is browning too fast, reduce heat slightly.
Rest & slice: Transfer the cooked quesadilla to a cutting board. Let it rest 1–2 minutes (this helps the filling settle). Slice into 4 wedges with a sharp knife or pizza cutter.
Repeat & serve: Repeat steps 3–6 for remaining tortillas/filling. Serve immediately with ranch or blue cheese dip and celery sticks if desired.