Season chicken with salt, pepper, paprika, garlic powder, onion powder, and cayenne.
Pour buttermilk over chicken. Refrigerate at least four hours or overnight.
Whisk together flour, cornstarch, paprika, garlic powder, thyme, oregano, and cayenne.
Remove chicken from buttermilk and dredge in flour. For extra crunch, dip back into buttermilk and dredge again.
Let chicken rest on a wire rack for 10–15 minutes.
Heat oil to 325°F in a deep skillet or Dutch oven.
Fry chicken in batches for 12–15 minutes, turning occasionally, until golden brown and cooked through.
Transfer to a wire rack and rest for 10 minutes before serving.