Dont buy this

nismored

I would scuff it up with a fine grit paper. I highly doubt it is a metal emblem that is literally chrome plated. I am fairly confident that it is plastic with a silver layer. I don't think i needs to be sanded, it just needs a rough surface to adhere. Do very light layers and take your time. You can wet sand in between sprays to get a really smooth nice look. Once you get a few layers of clear on there it should turn out nice and not chip easily.