When ready to cook, heat the oven to 425 F. Line a baking sheet with parchment paper and spray it with olive oil cooking spray.
In a shallow bowl, combine the whole-wheat and panko breadcrumbs. In another small bowl, whisk together the remaining 6 tablespoons of buttermilk, the mayonnaise, blue cheese and lemon juice.
Transfer to a ramekin for dipping. Pour the remaining 1/4 cup of hot sauce into a second ramekin for dipping.
Use a colander to drain the chicken, but do not pat it dry. Dip each chicken piece in the breadcrumb mixture, making sure it is coated well on both sides. Arrange the chicken in a single layer on the prepared baking sheet, then spritz the tops with olive oil cooking spray.
Bake on the oven’s middle shelf for 10 minutes. Turn the chicken pieces over and bake for an additional 5 minutes, or until they are just cooked through. Let cool for a few minutes, then transfer to a platter. Serve with both dipping sauces.