Caitlin Thorburn, who was the voice actress behind KOS-MOS, T-elos, and Nim in Xenoblade Chronicles 2 has stated on her Spotlight page that she has been working on a Xenoblade Chronicles game for release this year. Because of the roles she has played in Xenoblade Chronicles 2 many believe that Monolith Soft is preparing to release Xenoblade Chronicles 2 Definitive Edition. We will have to see how this plays out.
Thanks to Greatsong1 for sending in the news tip!

That doesn’t make a lot of sense unless they made new content for the game and had to bring her in the record new lines.
Well, we ARE talking about Monolithsoft here. So far, they’ve included extra content in all of their definitive editions. It’s really not that unlikely.
A Definitive Edition would be a dream come true for XC2.
Xenoblade Warriors maybe?
As I said, it wouldn’t make any sense if a Xenoblade 2 Definitive Edition is planned… no need to re-record the voices…
Especially since I find this release date strange, since when is a voice actor aware of that?
Anyway, we’ll see, but I prefer a Xeno 4 or a spin-off like X rather than yet another re-edition…
The updated listing specifically says the role is “Kos Mos”
Anyway, I don’t think a Xenoblade 2 DE makes any sense at all. Switch 2 can already play the game just fine, and the major flaws the game has would probably require a full remake to properly address. I also don’t expect she would record new lines for a simple “Switch 2 Edition” of the game unless they added some hefty content to connect with Xenosaga (which I also doubt they’re doing). If anything, that would just include some minor QoL improvements. I do expect at some point we’ll see free Switch 2 updates for the series though – simple resolution/framerate improvements.
My best guess is that it’s for Xenoblade 4/X2 or a spinoff like Xenoblade Warriors. I’d be quite happy with either of those.