According to recently rumors on NR, the upcoming Nikon full frame mirrorless camera will be shipping about one month after Photokina 2018 (in October). While the official announcement will be before Photokina, this is same as rumored before.
The upcoming NAB Show 2018 will be on April 7 to 12, 2018 in Las Vegas. Nikon USA has reserved a booth at the middle of the Central Hall. And the booth of Nikon is almost as big as other video-heavy-hitters like JVC, Fuji and Arri. While in 2016 and 2017, Nikon has no booth at NAB Show.
As rumored before, Nikon is planning to announce new mirrorless system cameras in 2018. Previous rumors said that the upcoming Nikon mirrorless camera will be full frame, now according to NR, it seems that Nikon may announce both DX format mirrorless camera and FX mirrorless camera in 2018.