Place each chicken breast between 2 pieces of plastic wrap and gently flatten with a meat mallet or heavy flat object to an even 1/3-inch thick.
In a shallow bowl add the chicken and the buttermilk. Cover and marinate for 1 hour in the refrigerator.
In a food processor, pulse pecans until finely ground. Transfer the pecans to a large rimmed dish and add the panko bread crumbs. Mix to combine well.
Remove marinated chicken breasts from buttermilk and shake off excess. Dip chicken in breading mixture, evenly coating both sides.
In a large nonstick skillet, heat oil. Add breaded breasts and shallow fry about 4 to 5 minutes on each side until golden in color. Remove from oil to and drain on paper towels. Immediately season with salt and pepper and place on a serving platter of individual dishes.
Serve it with a yummy salad for a super tasty meal. Enjoy!