Place chicken breasts in Instant Pot or slow cooker. Add half of the wing sauce and if using Instant Pot, cook on high pressure for 25 minutes, allowing it to naturally release the pressure once the chicken is done. If using slow cooker, cook chicken for 2-3 hours on high.
Once chicken is done, use two forks to shred it. Add it back into the cooker and toss it with the sauce. Set it aside.
Heat your grill to medium-high heat.
Arrange half of your chips in a 13x9" disposable pan. Sprinkle ⅓ of the mozzarella over the chips, then add half of the shredded chicken. Drizzle some wing sauce over it, if desired.
Top with another layer of chips, followed by another ⅓ of the mozzarella, then the remaining half of the chicken. Sprinkle with remaining mozzarella.
Place nachos on grill. Turn grill off and let nachos rest, covered, for 5 minutes, or until cheese is melted. Remove from heat.
Top nachos with carrots and celery. Drizzle with blue cheese or Ranch dressing. Sprinkle with green onions. Enjoy!
Recipe by Simple, Sweet & Savory at https://www.simplesweetsavory.com/grilled-buffalo-chicken-nachos/