Nickel plating is mainly for corrosion resistance. It was started with revolver cartridges carried by police in leather belt loops in all kinds of weather. The nickel plating seems to have variable quality. Some of it sticks well and wears off the brass gradually. Some of it flakes off, though, leaving thinner brass exposed underneath. Sometimes the plating process seems to have embrittled the brass so you get neck splits prematurely.
If you get flaking nickel, the nickle flakes can sometimes embed in resizing dies so the scratch up every other case they size. I actually had this happen to a carbide sizing die. I never did figure out how. Perhaps it found a surface crack to stick into? I've never tried annealing a nickel plated rifle case, but wouldn't expect that to go well, either.
I once bought 500 Remington nickel plated .308 Win. cases, figuring to be able to distinguish my cases from other shooter's brass at the end of a match. Instead, it turned out the white metal reflects surrounding color with such fidelity the cases were almost perfectly camouflaged in the grass and I lost of lot of them. No wonder nobody else was using them. 15 years later, I still have 300 new ones I've never loaded. I suspect I'll work up a load for my Steyr Scout with them just for hunting so I will have extra weather resistance and figure it will take a long time to lose that 300 if I only expend them in the field.
Bottom line, unless corrosion resistance is your primary concern, nickel is, in every other way except maybe lubricity in stripping from a magazine, inferior for handloading, IMHO. I would own a separate die for sizing nickel cases to protect the die I use for sizing brass cases.
