According to Famitsu (and by Famitsu I mean https://www.gematsu.com/2020/02/yggdra-union-well-never-fight-alone-coming-to-switch-on-march-5-in-japan) Yggdra Union will be released on the Nintendo Switch's eShop in Japan on March 5th. Cross your fingers that they'll release an English version at some point.
I always find myself here whenever I hear something Yggdra related in the news recently. I'm honestly hoping it does get localized.
Here's to hoping for an announcement for localization, though one month (not even) out is very short notice for release and it's unlikely they'd have localization plans if they don't already have significant progress on them.
My plan is to buy the game on the JP eShop if there are no localization announcements before its release day.
I hope it's localized, though I don't have much hope.