You are correct. Although Sweden was not in NATO as of making of this meme, Swedish was still included as one of Finland's official languages. I used the corresponding Wikipedia articles for translation, and the German one happened to use Organisation des Nordatlantiksvertrags or ONAV.

[–] Successful_Try543@feddit.org 2 points 3 weeks ago* (last edited 3 weeks ago)

I did already notice the German version Wikipedia is using in your other detailed reply. By that way: Thank you for the detailed list including also minor languages one at first wouldn't have in mind.
As the OC was refering to the "German way" of composing nouns, I also wanted to show how that would look like in that case.
Anyway, there obviously are at least two ways to 'translate' NATO into German and Wikipedia chose the boring one ;)