In a medium bowl, add the salt, pepper, onion powder, garlic powder, paprika, cumin, oregano, and cayenne and mix until combined.
Pour half of the spice mix into the flour, mixing until the spices are evenly distributed throughout the flour.
Add the chicken to a bowl, and sprinkle the remaining spice blend over it. Mix until all the chicken pieces are evenly coated.
Pour the buttermilk over the chicken, and stir until the residual spices from the chicken have blended in with the buttermilk to create a light orange color.
Marinate the chicken in the fridge for 2 to 8 hours.
Heat oil to about 325°F (170°C) in a large cast iron skillet.
Dredge each piece of chicken into the flour, shaking off any excess. Dip them back into the buttermilk mixture, then back into the flour. Make sure to shake off excess flour or it’ll burn while frying.
Fry 3-4 chicken pieces at a time, occasionally turning the pieces over. Cook for about 10-12 minutes, until golden brown and crispy.
Rest the chicken pieces on a wire rack to let excess oil drain off.