Peaches and nectarines are not suited to espalier because they are too vigorous.
Europeans do it, fanning the branches onto a sunny wall because otherwise their climate is too cold. Of course the trees are much less vigorous there. The French also have some unusual shapings.
If you really want to do it, then invent a system where you can replace the old wood each year with new 1 year old branches, which are the only branches which will fruit - quite different to apples and pears.