From Nintendo's twitter
*EDIT*
Sorry didn't see this was from a fake account. I'm dumb sorry. Can a mod delete this thread.
We have Partnered with @Xbox to bring Xbox one Controller Compatibility to YOUR #NintendoSwitch ! As of today you will be able to play your favourite games with the controller of your choice! Go and give it a try!
*EDIT*
Sorry didn't see this was from a fake account. I'm dumb sorry. Can a mod delete this thread.