There has been plenty of indications (this one, for instance) that Warner Bros. is preparing to revisit the Scribblenauts franchise in recent weeks. Now, the North American rating board ESRB has reviewed both the Switch version and the PS4/Xbox One version, which is pretty much as official as things get without the game actually being officially announced by the publisher.
This should also indicate that we're not far off from the release date, so it could drop very soon after the official announcement.