In a large saucepan over medium heat, stir together the hot sauce and butter until the butter melts and emulsifies into the hot sauce. Add the shredded chicken and stir to coat. Heat it in the sauce for a few minutes, stirring constantly, just until the chicken is heated through. Don't over cook or the sauce will separate.
Serve the shredded Buffalo chicken filling with warmed taco shells or corn tortillas, lettuce, green onions, celery and/or crumbled blue cheese or blue cheese dressing, as desired.