I have pairs of Crocket and Jones and Loakes in waxed nubuck and waxed leather. You can buy a cream specially for waxed leather or as I do, just put a very light coating of dubbin on them when needed. Incidentally, Loake's waxy leather protector is just dubbin.
Waxed leather shouldn't need much upkeep though. I'd first try buffing the leather with a cloth to get the impregnated oils to the surface in the first instance. You shouldn't use ordinary wax polish on waxed leather either. It will create its own natural patina over time.