4boneless skinless chicken breasts or fillets(not too thick, about 5 oz. each)
Preheat the oven to 400 degrees.
Place the pistachios in a food processor and pulse until they turn into small crumbs. Pour the pistachios into a shallow dish. Add the panko and toss to combine.
Pat any excess moisture off of the chicken breasts using paper towels. Brush the honey mustard onto both sides of the chicken breasts (or you could rub it on if you don’t have a brush). One at a time, place a chicken breast into the dish with the pistachio mixture. Press the pistachios into the chicken until the chicken is well coated on all sides. Discard the extra pistachio mixture.
Place the chicken on a baking sheet that has been sprayed with cooking spray or lined with parchment paper. Bake until the chicken is cooked through and juices run clear (about 25 to 35 minutes, depending on the thickness of the chicken breasts).
I used chicken breasts that were about 1-1/2 inches thick. Don't use chicken breasts that are too thick. Otherwise, they will take longer to cook and the nuts may burn.