Cultural Assimilation is Cultural Assimilation either the Borg way or the Federation way...
I personally don't think the usual discourses of cultural assimilation apply in either of these cases, but as I said previously, this reading is available (at least in the case of Nog you raised). I just don't find it compelling.
A few small follow on points....
Since Nog lives on a Bajoran station, if this were a textbook case of cultural assimilation, the question might be expected to hinge upon his taking on traits from Bajoran culture. He doesn't. He chooses to join Starfleet. As far as we know, there's nowhere in the Federation where cultural assimilation in the textbook sense could apply to a Ferengi, although this doesn't mean that you couldn't make a case with another species. (I'm not denying that cultural assimilation COULD be applied to the Federation in some context, I just don't find it applicable to Nog's circumstances.)
And Borg assimilation is categorically NOT cultural assimilation in the way this term is typically used, because you do not get to be a minority culture in a host culture when the Borg assimilates your species - you go straight to Borg, do not pass sector 0-0-1, do not collect any gold-pressed latinum.
Thanks for opening the discussion, anyway! I found it stimulating to consider this argument, even though I am not personally convinced by it.