When NATO issues the medal it comes as a cased set with clasp on the medal and a bar on the ribbon. It is also accompanied by a presentation certificate.

The Office of the Under Secretary for Personnel and Readiness maintains a list of "Approved Military Decorations and Awards" which is a roster of the approved Joint DoD awards and/or operations for which the medal is authorized.
This is the DoD Approved NATO Medals for Acceptance and Wear approved award/operations. as of the date shown in the document. You may want to verify if it has been updated at The Office of the Under Secretary for Personnel and Readiness (linked above)