Preheat your oven to 375.
Spray a 9" x 9" baking dish with non-stick spray.
Bring a large saucepan of water to a boil. Add the chicken and poach until cooked, 10-15 minutes depending on how thick the chicken is.
Remove and let cool slightly then shred with a fork.
Transfer chicken to a large bowl and add the entire bottle of wing sauce. Stir to combine well.
Pour the chicken into the baking dish and spread out evenly.
Add the cream cheese and Ranch dressing to a medium saucepan over medium heat. Stir until the cheese is melted, then whisk until smooth.
Pour the cheese mixture over the chicken and spread out evenly.
Sprinkle top with the celery.
Bake for 15 minutes.
Sprinkle top with cheese and bake another 10 minutes until hot and bubbly.
Remove and let rest for 10 minutes before serving.