Preheat the oven to 350°F. Sprinkle the chicken with the salt and pepper and place in a rimmed baking sheet or in a baking pan. Bake for 25 to 30 minutes or until a meat thermometer inserted in the thickest portion registers 165°F. Remove to a plate.
Cut the chicken into large chunks and add to the bowl of a food processor. Pulse until the chicken is shredded. Remove to a large bowl to cool completely.
Meanwhile, cook the bacon in a cast-iron skillet until browned and crispy. Remove to paper towels to cool. Chop or crumble into small pieces.
Stir together the mayonnaise and Ranch dressing mix in a small bowl.
Add the bacon, mayonnaise mixture, celery, and cheese to the shredded chicken and stir until coated. Refrigerate until ready to serve.