Nordic Aliens

The website doesn't use the terms “Nordic Aliens” or for that matter “Aliens”, because it doesn't have anything to do with the original story.

But the term does have its own position on the website, assuming of course it originates from 'George Adamski' and 'Howard Menger' and not 'David J. Skal' - under Other Contactees#Frauds.

Thoughts and opinions
The Scandinavian Peninsula became ice-free around 11,000 BCE, i.e. at the end of the last ice age, see Scandinavian prehistory (Wikipedia), thus the “Germanic Aliens” would make for more sense - but with these fantasy authors 'sense' doesn't necessarily unconditionally fit into it. The Plejaren Federation incidentally are multicultural i.e. containing several cultural or ethnic groups, so it wouldn't work even if it wasn't made up. As stated before, the website doesn't use the term because it doesn't have anything to do with the original story.