http://3.bp.blogspot.com/-6fB2zb0PHoU/VLbKHSsivoI/AAAAAAAAhko/L_NmRvjcJP4/s1600/Nidalee_Splash_7.jpg
That weapon looks more like Sivir's Boomerang than a Nidalee spear. I think Riot is trying to trick us on this one with the label.
EDIT: Just realized, the figure in the back looks like 
WOW IF THAT'S NID IN THE BACK.... SHE LET HERSELF GO
Well it's definitely not a Nidalee skin, definitely disguised.
I would guess Sivir because Nid is already getting a WK skin. Why make two for Nid in such a short time?
AFAIK, they are confirmed to be Justicar Sivir and Nautilus.
Its clearly a sivir splash but idk if im sold on the nautilus idea, i would like to believe its Azir. After all Sivir was recently saved after her blood resurrected Azir and this could be their coming to power over Shurima
