In a wide bowl, combine the flour, cornstarch, garlic powder, paprika, salt, onion powder, and black pepper.
In a deep skillet or saucepan, heat the oil over medium-high heat.
Remove a piece of chicken from the buttermilk, allowing the excess to drip off, and coat in the flour mixture. Add to the heated oil with a few more pieces of coated chicken, being careful not to overcrowd. Fry until golden, about 3-5 minutes per side, and transfer to a towel-lined plate. Repeat with remaining chicken.
While the chicken is frying, preheat oven to 375˚F. Arrange the waffles on a baking sheet and bake until toasted and heated through, 12-15 minutes.