Epic says there are 20 Switch titles being worked on in Japan using Unreal Engine 4

Coming from Epic Games Japan representative Takayuki Kawasaki...

“Unfortunately, there were not any Unreal Engine titles at launch, but in late March, Snake Pass, which was one of the titles playable at GDC, launched in America and Europe, and at the Nintendo Switch Presentation, there were titles such as Shin Megami Tensei. In Japan, there are about 20 titles being developed that use Unreal Engine, so I think that they’ll be announced gradually from here on.

These are titles that use Unreal Engine, for Switch, and are being made in Japan. There may even be more. And now we’re gradually moving forward with Switch support for the free version [of Unreal Engine 4]. That way, as long as you have a Switch development license, you will be able to develop for Switch even with the free version.”

As Mr. Kawasaki says, that's just in Japan alone, and there could be more in the pipeline. Pretty encouraging news, especially this early on!