Put the hot sauce and butter in a small skillet and heat until melted and combined. Let cool slightly, then pour over the shredded chicken in a medium bowl and toss to coat completely.
To assemble the sandwich, spread the chicken in an even layer on the bottom half of the bread. Top with the sliced celery and an ample amount of shredded lettuce. Spread the Blue Cheese Ranch on the top half of the bread and close the sandwich, using toothpicks to secure it. Cut into pieces and serve.
Blue Cheese Ranch:
Stir together the blue cheese, mayonnaise, sour cream, chives, vinegar, onion powder and garlic powder in a medium bowl until well incorporated. Season with salt and pepper.