Nickelling or Chroming

I am no mettalurgist but From the little i know nickelling requires a polished surface to look good so the original metal would have to be all but perfect which no car is even new. chroming uses copper as a polishing base so would be easier to acheive i think.
Nickelling is also a prechroming process as nickel is not quite so resisitant to the open element as chrome would be.
There is also available Chrome look paintswhich arent obviously as good but would be cheaper.
If money is no object or you are a plating specialist and can do it yourself you can have whatever your heart desires. there are other options like multilayer paints that change colour as you look at the vehicle from different angles.
You are best asking a hotrod specialist or a bike specialist as they get to do this on a smaller scale

The 2nd pic you posted is part of the mercedes calendar of some year, they had the same effect on many cars, i think they did it by using reflective film applied to the paint, kind of like a window tint, so that is another option, though you would need a professional install to iron out all kinks and edges