My Fenix LOD also looks like crap, which is why I plan on finding some way of never putting anything with dark anodizing on my keychain after I replace this otherwise great light. Type III anodizing is tremendously overhyped- as far as I can tell it was originally specified to help protect against corrosion, which is nearly negligible on aluminum. I've never had anything with this hard anodizing that didn't scratch, either from casual use or small drops.
I don't know what type of anodizing your Nano has on it, but I guess my point is that there is no type of coating that won't scratch, and the dark colors just emphasize whatever small scratches occur to your light. I can't imagine why anodizing is still so popular on keychain lights despite how freaking bad they look after a relatively short period of carry.