Although Bandai Namco was deeply involved with the development of Super Smash Bros. for Nintendo 3DS and Wii U, Nintendo has yet to formally confirm whether the studio is also working on Super Smash Bros. for Nintendo Switch. However, according to a now-deleted tweet from Nintendo software engineer Tiago Sonobe, Bandai Namco is indeed developing the upcoming fighting game as well. It turns out that Sonobe has also deactivated his Twitter account, so it looks like he didn’t intend to leak any undisclosed information:
https://twitter.com/IceDoesntHelp/status/994394487647621120
https://twitter.com/IceDoesntHelp/status/994397923277443073
Source: IceDoesntHelp @IceDoesntHelp