Grow it as a garden tree. It is most likely grafted. Enjoy the fruit. Nectarines and peaches are varieties of the same species of fruit tree. Peaches are naturally fuzzy, which is an adaptation to low humidity environments, nectarines are a no fuzz variety of peach. In breeding out the fuzz from peaches, the flavor of nectarines was shifted slightly, so they do have a different flavor profile, but they are varieties of the same species and can interbreed.
A peacherine tree is a trunk of grafting understock with individual branches of both peach and nectarine varieties grafted onto the understock.
Grow it in your garden. Mark which branches give you your favorite flowers or favorite fruit. Then air layer off part of that branch to make your bonsai. It does mean growing it out a few years.
If you are in a hurry, sure, just slap it in a pot. If you chop too low you will end up with only the understock which is likely a wild plum variety chosen for disease resistance rather than flowers or fruit.
Understock will have white flowers, peaches and nectarines have deep pink flowers.