Coat the chops first in the mustard and then in the brown sugar. Season with a little salt and pepper. Cook on a preheated barbecue or grill for 3-4 minutes on each side.
In a large bowl, whisk together the lime zest, juice and olive oil. Add the beans or peas, cherry tomatoes, scallions, red onion, nectarines, avocado and most of the mint leaves to the dressing in the bowl and mix gently. Season with salt and black pepper. Scatter the reserved mint leaves over the salad.