According to IMDB; Nina is rumoured to be guest starring in season 4: episode 13 of The Originals as one of Nina’s most likeable characters, Katherine Pierce, although IMDB is so confident it will happen that Nina’s appearance is not listed as a rumour. It is not confirmed if Nina will be recurring through multiple episodes of The Originals as Katherine Pierce, so it can only be assumed at this time that Katherine will play into the storyline in some capacity, although it would be nice to see Nina remaining in The Originals for a run of episodes.

Some may question the legitimacy of the source given that there is no clear indication of who informed IMDB of this being 100% confirmed. However, it is important to notice that IMDB listed Nina as specifically appearing in season 8 episode 16 of The Vampire Diaries before we received 100% confirmation from elsewhere of Nina’s appearance and the additional fact of season 8 only being a 16 episode season.