Ikumi Nakamura tweets, the network goes crazy, the portals misunderstand.
No, Okami 2 it is not in development. At least not yet. But let's proceed in order: at 16:38 pm today 18 October 2019 Ikumi Nakamura posts the tweet of discord. Nakamura had once been Einviroment Artist for the original Okami, before transitioning first to Platinum Games and then to ZeniMax (working as Creative Director for Ghostwire: Tokyo). One can therefore reasonably speak of a person informed of the facts, but in practice he currently works as a freelancer and, above all, has no ties to either Platinum Games or Capcom, which currently holds the Intellectual property by Okami.
The Tweet, not surprisingly, after the initial statement "Okami is about to return" simply goes on to say that they (reasonably, she and Platinum Games) they want to work to Okami 2 and fans of the series are craving a sequel as well. The post then closes, in fact, by tagging the official American account of Capcom and that of Okami, in Japanese.