Prepare the Slow Cooker:Spray your crockpot with nonstick cooking spray for easy cleanup.
Add Chicken and Seasonings:Place chicken breasts into the crockpot, arranging evenly. Sprinkle ranch dressing mix and au jus gravy mix evenly over the chicken.
Add Pepperoncini and Butter:Pour pepperoncini juice over the seasoned chicken. Add pepperoncini peppers on top, and place butter slices evenly across the chicken breasts.
Cook:Cover and cook on LOW for 6-8 hours or on HIGH for 3-4 hours, until chicken is tender and easily shredded with a fork.
Shred and Serve:Once cooked, shred the chicken with two forks directly in the crockpot, mixing well with the flavorful juices.
Enjoy:Serve hot over mashed potatoes, cooked rice, pasta, or on sandwich buns. Garnish with additional pepperoncini peppers, if desired.