In order for that split to make any sense topics in the current General UK Immigration forum would need to be split between that and any new Nationality forum.
Just a little problem with that .... there are currently 1180 topics! I suspect that you would get no volunteers to undertake that massive task.
But are immigration and nationality so different? They are IMHO extremely intertwined. Take for example the post I have just made in
this topic. It is certainly an immigration-related subject .... but are you saying I was wrong to also cover the naturalisation aspects that follow from that? And exactly where would that leave that topic in the new split situation?