Place the chicken breasts in the base of the slow cooker and sprinkle the ranch dressing mix over the top. Pour the buffalo wing sauce over the top.
Set on low and cook for 8 hours. Once the chicken is cooked, shred with 2 forks and combine with the sauce.
Preheat the oven to 400 F.
Assemble the nachos on baking sheet with tortilla chips, shredded buffalo chicken and shredded mozzarella cheese on top.
Bake in the preheated oven for 10-15 minutes, or until cheese has melted.
Serve Buffalo Chicken Nachos with crumbled blue cheese and chopped celery garnish, and side of fruit.