Place chicken pieces in a bowl, cover with the buttermilk and marinade for 30 minutes at room temperature.
In a food process, pulse the pecans, flour and all seasonings until the nuts are roughly chopped.
Transfer the pecan mixture to a bowl and, one at a time, coat the chicken pieces thoroughly.
Set the coated pieces on a baking sheet, cover with plastic wrap, and refrigerate for at least 30 minutes.
Fill a cast-iron skillet halfway with olive oil and heat over medium-high heat until hot but not smoking.
Cook the chicken 2 to 3 minutes per side, or until dark golden.
Drain the chicken on paper towels and serve hot.