get another wheelnut of any scrap vehicle , one thats slightly smaller than the rangie one in diameter . arc weld the nuts to eachother but use plenty of amps to get penetration , ie
120A and 2.5mm rods .
by using a 1" AF or similar nut you should have enough surface on the RRC nut to get a good weld to and then you should be able to use a knuckle bar to get it off .
series 2a wheel nuts would be ideal and you can even stick a welding rod down thru the hole to get an extra weld in place .
i would have thought though that the original RRC nut would have some flats left on it down inside the hole in wheel with which you could get a decent hexagon socket onto .
no need for tig welder but keep rod away from ali rim and have water by youre side so you can cool off the weld quickly .
you should be able to save the wheel and not damage it