Nissan (@Nissan) June 2, 2014
The tweet was published on Nissan's global feed, rather than a regional one, which may suggest a vehicle for multiple regions. That hints that this might be our first look at the platform for the next-generation Frontier because it's sold in several countries around the world as the Navara pickup. From the teaser image, you can easily make out the truck's grille and LED running lights. It also appears to have roof rails on top. The new Titan is probably a less likely candidate because it's only available in North America, and it's already rumored for a reveal at the 2015 Detroit Motor Show.
To mark 80 years of pickups, Nissan also released a brief video showing off past models and looking toward the future by displaying the same model under wraps. Scroll down to watch it.