During its E3 conference, Square Enix revealed through a very small teaser that NieR will be getting a sequel. Little is known about the game, including its full name. However, we do know that it will be developed by Platinum Games, perhaps best known for Metal Gear Rising: Revengeance and the Bayonetta series. In addition, the game will be directed by Yoko Taro, who made an appearance on the E3 stage in a mask themed after Emil from the first game.
NieR’s sequel will be a PlayStation 4 exclusive, with more information coming this autumn.
Source: Square Enix E3 Conference