Unfortunately, Nina’s guest starring role as Katherine Pierce in Season 4: Episode 13 of The Originals has been removed from Nina’s IMDB profile. Upon first glance; this may mean it was just a wild rumour and will not be happening. However, on second glance we have technically all been here before regarding Nina’s appearance in The Vampire Diaries finale. If you recall, IMDB actually listed Nina’s appearance in the final-ever episode of The Vampire Diaries while almost everyone elsewhere was reporting that Nina would not be returning in addition to the fact that the listing specifically referred to Season 8: Episode 16 before it had even become public knowledge that the final season would be 16 episodes.
There are reports that Season 4 could be the final season of The Originals due to its reduced length from 22 episodes to only 13 episodes. If Season 4 is to be the final season, then it would make sense to have Katherine Pierce or another doppelganger feature in some way to show how the Petrova bloodline would continue to evolve or for Katherine to finally get her revenge on Klaus. The involvement of a Petrova doppelganger could perhaps even lead to an important element of a spin-off series containing characters from The Vampire Diaries and The Originals.
If Nina is officially confirmed for a guest starring role as Katherine Pierce or even another doppelganger in The Originals: Season 4 – Episode 13, then we should expect to hear an official announcement within the next few weeks as The Originals: Season 4 began airing on The CW on March 17th 2017.