According to Redditor _darth_solo_, Bayonetta 3 will be releasing for Nintendo Switch some time in 2018. Solo stated..
I cannot personally reveal my source, but I have it on good authority from a reliable source that Bayonetta 3 will be released this year, maybe this summer. It will not be released later than 2018 barring a disaster.
I have confirmed my sources with the mods, u/FlapSnapple gave me the go ahead for this, so they can vouch for it. I’m sorry but I can’t say much more other than watch out for the Nintendo Direct because Bayonetta 3 will be one of those placeholder games that Nintendo is preparing to release. This direct may be Nintendo’s E3 if what we’ve heard is true.
While is sources were confirmed by moderators of r/NintendoSwitch, it is still unclear where this information comes from.