https://www.polygon.com/2018/9/13/17857490/nes-classic-controllers-nintendo-switch-price-release-date-joy-con

Nintendo announced that the company will be releasing special NES controllers for the Nintendo Switch.

These retro controllers are super cool and identical to the originals, but they unfortunately are only compatible with the Nintendo Switch Online’s NES games. That means no, you will not be able to play Breath of the Wild or other new games with these.