Position a rack in the center of the oven. Preheat the oven to 400°F. Spray a wire rack with vegetable oil spray and place it in a roasting pan or on a baking sheet.
Rinse the chicken breasts in cold water, then place them in a resealable plastic bag with the buttermilk and hot sauce. Close the bag, shake until the chicken pieces are fully coated, and refrigerate for at least 2 hours or overnight.