WWE 2K18 finally came out for the Nintendo Switch, but sadly the game is somewhat unplayable especially in handheld mode.
As noted by Kotaku, the main issue with the Nintendo Switch version of WWE 2K18 is the very low framerate. It seems as if you are playing the game in slow motion.
Not to mention the graphics have been downgraded to the PC, PS4 and Xbox One versions. The Switch version is supposed to run at 30fps, but it looks like it drops far lower than that.
YouTube user Gaming By JC uploaded a video so you can see how the game runs on the Switch. Hopefully a patch of some sort is released in the near future to fix the performance issues.