In a large bowl, whisk the olive oil, mustard, white wine, garlic, and dried thyme together. Add the chicken, turning to coat. Cover tightly and refrigerate for at least 4 hours and up to 12 hours.

In a shallow dish such as a 9-inch square baking pan or a pie dish, combine the walnuts, flour, salt, and pepper together. Remove the chicken, shake off any excess marinade, and dip both sides of the chicken in the walnut mixture. Make sure each side is generously coated.

Preheat the oven to 425°F (218°C).

Heat 1 Tablespoon of olive oil in an oven-safe skillet* over medium heat. Add the chicken and sear for 2 minutes, 1 minute on each side. Transfer skillet to the oven and bake, covered loosely with aluminum foil, for 15–20 minutes or until the chicken is fully cooked through. (Chicken is considered done when an instant read thermometer reads the center of the thickest part as at least 165°F (74°C).)

Whisk the glaze ingredients together and serve with chicken. Garnish chicken with fresh parsley, if desired.

Leftovers keep well in the refrigerator for a few days. You can reheat on the stove over medium heat, in the microwave, or in the oven.