Prep & Marinate: Place chicken breasts on a plate. Pat dry and sprinkle both sides with salt and pepper. Move chicken to a bowl and pour buffalo sauce over top; mix to fully coat the chicken. Let sit 15-30 minutes.
Prep Grill: Heat grill to medium heat (approximately 400-450 degrees F). Ensure grill grates are clean and rub with olive oil or your favorite non-stick cooking spray.
Grill Chicken: Place chicken on direct heat (over direct flame) and cook at medium heat for 4-5 minutes per side. Move chicken away from the direct heat (direct flame) so that it is cooking on indirect heat (maintaining the same grill temp) and cook for an additional 5-10 minutes (you don't need to flip during this point because the chicken will cook as if it is in an oven) or until the internal temperature of the thickest part of the chicken reads 160 degrees F on your meat thermometer.
Rest: Remove from grill and let rest at least 5 minutes (the chicken will continue to cook during this time and the internal temp will continue to rise up 5 additional degrees). Chicken is safe to eat when it reaches an internal temp of 165 degrees (at thickest part of the breast).