Stack 2 large sheets of heavy-duty Reynolds Tin Foil and form into a pan by turning up the four sides. Place the chips, then the cheese, beans, and avocado in the pan and transfer to the grill. Grill the peach next to the nachos, cut sides down. Cover the grill.
Grill the nachos until the cheese melts, about 6 minutes. Grill the peach until just softened, about 3 minutes. Transfer the peach to a cutting board. When cool enough to handle, coarsely chop. Stir into the salsa.
Transfer the nacho pan to a serving platter and spoon the salsa on top.
