Seems like there was no fire to this smoke.
There have been multiple rumors about Ni no Kuni 2: Revenant Kingdom, the sequel to the 2013 hit PS3 JRPG, coming to the Xbox One as well. The game, which was originally announced as a PS4 exclusive, was eventually revealed for PC as well. However, an Xbox One version did not seem entirely out of the question, since Bandai Namco has upped its support of the Xbox One in the last few months.
The reports included retailer listings, as well as a scoop from IGN Spain. However, it seems like said reports were false- Bandai Namco has definitively confirmed to Gematsu that the game is not going to be launching on the Xbox One- so if you want the game, you need to get it on PS4 or PC.
It makes sense- the title is being developed by Level-5, who have famously never developed a game for Xbox, after their MMORPG for the original Xbox ran into trouble and had to be canceled (leading to rumors of bad blood between Microsoft and Level-5 lingering to this day). Sadly, it seems like that may not have changed for now.
Bandai Namco's response to Gematsu regarding Ni no Kuni II for Xbox One rumors: "Ni no Kuni II is only in development for PS4 and Steam." pic.twitter.com/xfTSsg2Oos
— Gematsu (@gematsucom) October 19, 2017