Nametags are not listed on the "Prohibited Items List" in the DoD Government Charge Card Guidebook.  While this is not an all inclusive list, I could not find any specific restrictions for name tags, patches or for any items related to uniforms or clothing in general.  However, it is possible that your local agency or higher headquarters have imposed restrictions for this type of purchase, so I would ask your cardholder to show you the specific policy or regulation this purchase would violate.  You could also request for the cardholder to obtain an outside review of this purchase by the A-OPC, general counsel and Financial/Resource Manager from your local base.  Ideally, one or more of these folks should be able to identify what local policy or regulation this would violate and hopefully tell you what other alternatives you have if it is a prohibited purchase.