Trim any fat from the chicken breasts and lay them into the bottom of a 6 quart slow cooker.
To a small microwave safe bowl, add half the butter along with half the hot sauce, half the brown sugar, and half each of the onion powder, garlic powder, and salt.
Heat until melted, stir together, then drizzle evenly over the chicken.
Cover and cook on LOW for 6 hours or HIGH for 4 hours.
Once the chicken is cooked through, remove it from the crockpot, shred, and pour out any juices from the crockpot. Return the shredded chicken to the slow cooker.
In a small sauce pan over medium high heat add the remaining butter, hot sauce,  brown sugar, onion powder, garlic powder, and salt and bring up to a bubble, stirring occasionally.
Let the sauce simmer for 2-3 minutes or until slightly thickened.
Pour the sauce over the shredded chicken and use tongs to evenly coat.
Serve on a toasted brioche bun with pickles and ranch dressing.