In a medium pot, boil chicken over medium-high heat until no longer pink.
Drain. Add chicken to a medium bowl and shred chicken.
Melt butter in a large frying pan, or skillet, over medium heat.
Sauté onions until translucent then add shredded chicken and seasonings. Stir to combine then add buffalo sauce. Stir and let cook for 3-4 additional minutes.
Wrap tortillas in damp paper towels, 10 at a time, and place on a microwave safe plate.
Heat for 30 seconds and set aside. Then after filling, heat the remaining tortillas.
Add shredded cheese to over half of the tortilla followed by the shredded chicken down the center.
Roll up tightly and place seam side down and filling the remaining tortillas.
Preheat the air fryer at 390° for 2 minutes.
Place 4 chicken flautas on the disposable liner in the air fryer basket.
Lightly spray flautas with cooking spray and air fry at 390° for 6 minutes, flip, lightly spray flautas again, and cook for another 3 minutes.
Carefully remove from the air fryer basket and continue cooking the remaining flautas.
Serve with ranch dressing, blue cheese dressing or buffalo sauce.