There are quite a few “X·ish language” sites online by now, and they seem to be really useful for learners to ask native speakers.
Each of the nordic countries is probably too small to have an own SE. (E.g. Norwegian seems to have been deleted.) But the Danish, Norwegian and Swedish languages are pretty similar, and so I think a shared site for the three of them could get enough users that might still be able to understand many of the questions.