Add buttermilk, buffalo sauce, salt, and black pepper to a large mixing bowl. Mix the ingredients.
Pat the chicken pieces dry and place them in the buttermilk mixture. Make sure the mixture coats them completely.
Cover the bowl with Clingfilm and place them in the refrigerator to marinate for about 4 hours.
Before cooking, take the chicken out of the refrigerator for at least 30 minutes.
In a shallow dish or a bowl, add all the dry mixture ingredients, i.e., all-purpose flour, cornstarch, onion powder, garlic powder, Italian seasoning, paprika, and salt. Mix well.
Heat vegetable oil in a deep frying pan. It should reach 350 degrees F.
Take out the chicken thigh from the buttermilk mixture and place them directly in the dry mixture. Drench it a couple of times to ensure the dry mixture sticks to the chicken completely.
Carefully place the chicken thigh in hot oil and fry it for about 7 to 10 minutes or until the internal temperature reaches 165 degrees F.
Serve the fried chicken with mashed potatoes or any of your favorite sides.