It hasn't been announced whether it'll be a new main title, a port, or a spinoff, but the generic Tales of Series logo has appeared in a list on Nintendo's Japanese site of third party games to be released on the Nintendo Switch in the future (circled in red below).
A trailer for the second season of Tales of Zestiria the X has been uploaded. The opening theme by Minami is featured, though a title isn't given despite the new episodes starting tomorrow. The single will be released February 22 and I will post the full information once it's up.
EDIT: Replaced video with subtitled version uploaded by Daisuki
I'm a few days late, but FUNimation has announced they will be dubbing the second season of Tales of Zestiria the X, continuing from the previous season. The first episode will be up on January 22 at 10:00 pm ET. (Note that despite FUNi's recent partnership with Crunchyroll, the subtitled simulcast will not be available there.)
As previously mentioned, the new ending theme for Tales of Zestiria the X will be "INNOSENSE" by FLOW releasing on February 8, and as promised I'm posting the full release information now that it's out.
There are three editions, the standard CD, a limited CD+DVD edition, and another limited CD+DVD edition with anime art and more Tales focused music/video choices (pictured above).
Daisuki.net recently announced some upcoming titles to be streamed which includes the second season of Tales of Zestiria the X. New episodes will be available to view outside of Japan and China starting January 8 with subtitles in English, German, French, Italian, European Spanish, Latin American Spanish, Brazilian Portuguese, Russian, Traditional Chinese, and Thai. (From ANN, since Daisuki just linked back to them)
No news yet on whether FUNimation will still do a quick dub like the first season.