While the Nintendo Switch is mostly a solid piece of hardware it (at least) has one glaring fault. It has no way to store savegame data outside of the system. Thankfully, Nintendo have just unveiled more details of their Switch Online Service and it includes cloud saves.
The service is set to launch in September 2018 (a year later than initially planned) and will cost 20 bucks for a full year. For that you get to enjoy online play, play 20 NES games (with online support) and save your savedata to the Nintendo cloud. If you want more details, check here.
So let’s hope you don’t break your Switch before September and lose that 200+ hour Zelda save!