Square Enix has been showing a lot of support for Nintendo Switch, with the company releasing titles such as I Am Setsuna and Dragon Quest Heroes on Nintendo's new console. Seeing as several Kingdom Hearts titles were released on Nintendo platforms, it wouldn't be surprising if Kingdom Hearts III were to come to Switch.
In an interview with IGN, Kingdom Hearts Series Director Tetsuya Nomura was asked about whether or not a Switch version of Kingdom Hearts III was in the plans. Nomura answered that it "maybe possible" for Kingdom Hearts III to appear on Nintendo Switch, but only after the game releases on PS4 and Xbox One.
The Nintendo Switch is definitely a very interesting piece of hardware, but if we lightly say, ‘Oh yeah, we’ll be on the Nintendo Switch,’ I’m sure people will come back and say, ‘But what about the PS4 and Xbox One? We want them out first. Don’t focus on other platforms. So for now, we want to focus on what platforms we’ve already announced we’re going to be releasing Kingdom Hearts 3 on. And so after, perhaps, maybe we can start thinking about other possibilities.
Nomura was also asked if there's a possibility of the Kingdom Hearts HD Collections coming to Xbox One, to which he replied that the team is just focusing on Kingdom Hearts III for PS4 and Xbox One for now. However, he adds that he isn't sure if there's enough demand in the west to have the HD collections on Xbox One.
Just like with the previous answer, if we were to announce yet another non-Kingdom Hearts 3 [project]...people are going to be like, ‘Hey, what’s going on?’ So we will want to focus on releasing on the platforms that we have already announced. Do the Western audiences want Kingdom Hearts titles on the Microsoft or Xbox platforms? Japan might say ‘well, we don’t want any more on Xbox.
Kingdom Hearts III releases in 2018 on PS4 and Xbox One.