Sounds like making it from plastic then sending it for chrome plating (like the chrome bumpers in a plastice car model kit) would be the best bet. Whether you 3-d print it or build it up from sheet plastic, the surface finish will need to be as polished as you can get it before sending it off.
Hereâs one such service I found - not a recommendation, just an example:
http://www.mmmetalizing.com/services.html
You can also spray paint an âalmost like chromeâ finish. And there are spray coatings that use a base coat, a metallic powder (which can then be polished) and a clear coat. One type is Alclad but there are others. http://www.austinsms.org/Alclad-Lacquer-Metal-Finishes.php Many of these spray finishes are not very durable - scale modelers who build polished-metal aircraft typically handle their models as little as possible, and wearing cotton gloves when they do.
Try searching for scale model plating services, car model parts plating, that kind of thing. FineScale Modeler magazine and Scale Auto magazine are good resources as well.