Place the chicken in a large bowl. Mix with the salt. Pour the sweet tea over the top so that the chicken is fully covered. Cover and place in the refrigerator for 2-8 hours. Drain and pat the chicken dry.
Pour the buttermilk into a small bowl. In another bowl, whisk together flour, cornstarch, baking powder, salt, paprika, garlic powder and cayenne.
Place the chicken in the buttermilk. Remove, allowing the excess to drip off. Dredge in the flour mixture. Toss until evenly coated, pressing the mixture into the chicken with your hands. Shake off any excess flour and transfer to a baking sheet.
Heat approximately ½ inch of vegetable oil in a large cast iron skillet over medium-high heat until the oil reaches 350°F. Working in batches, transfer the chicken to the skillet and cook for 2-3 minutes on each side. The chicken is ready when it is golden brown and the internal temperature reaches 165°F. Transfer to a wire rack to cool.