how to properly paint chrome plastic

Yes it is best to use a self etching primer and it is not necessary to sand the chrome if you us a chemical cleaner/etcher on the chrome first such as liquid sandpaper this way you get a much cleaner smoother surface to start with without scratching or ruining the surface of the chrome. Thus if you don't like the paint job you can strip the paint back down to the chrome and throw some polish back on it and you good to go.