Preheat oven to 350 degrees F. In a medium-sized mixing bowl, whisk together the mustard and honey.
Toss the pecans in a food processor and pulse until the nuts are finely chopped. Pour the chopped pecans into a large bowl and set aside.
Using a paper towel, remove any excess moisture from the outside of the chicken breasts.
Taking one chicken breast at a time, roll the chicken in the mustard-honey mixture and coat on both sides.
Transfer the coated chicken into the chopped pecans and again cover both sides.
Place the crusted chicken into a greased glass baking dish and sprinkle each chicken breast with just a little sea salt if desired. Bake 45 minutes or until the chicken juices run clear.