https://wccftech.com/nintendo-switch-virtual-console/

Unlike other modern Nintendo consoles, the Nintendo Switch has yet to receive any way to play older games, not counting the NES games available as part of the Switch Online. It seems like, however, that things will be changing soon.

Twitter user KevDoy has confirmed recently that a Virtual Console section has been added to the eShop JavaScript Object Notation. Categories include SNES, GB, GBC, Nintendo 64 and Nintendo DS.