It's not right to say that only one is real. That's biased thinking, and shows that you're trying to push politics rather than find the truth.

Furthermore, the organization you're talking about isn't even NAS -- it's NASEM: the "National Academies of Science, Engineering, and Medicine". [1,2]

[1] https://nationalacademies.org/

[2] https://twitter.com/TheNASEM

This was all described in the article.

Furthermore, there are a bunch of other groups with the acronym NAS:

    Nationaal Arbeids-Secretariaat", a trade union federation in the Netherlands from 1893 to 1940
    National Academy of Songwriters, a music industry association for songwriters
    National Apprenticeship Service, the official UK government body responsible for apprenticeship coordination
    National Archives of Scotland, in Edinburgh, Scotland
    National Association of Scholars, an educational organization based in the United States
    National Association of Schoolmasters, a former trade union representing teachers in the UK
    National Association of Seadogs, a Nigerian confraternity
    National Audubon Society, an American environmental organization dedicated to conservancy
    National Autistic Society, an autism-related charity in the United Kingdom
    National Salvation Front (South Sudan), a South Sudanese militant group
    Nautical Archaeology Society, a British archaeology charity
    Nord Anglia International School Dubai

These are all very real.