https://thenextweb.com/gaming/2020/04/24/nintendo-confirms-160000-switch-accounts-were-breached-in-april/

Nintendo today confirmed the rumors we’d been fearing in recent days: multiple online Switch accounts had been hacked. The company says ‘about 160,000’ accounts may have have been subject to the breach. This allowed the thieves to make unauthorized purchases, explaining the reports of hackers stealing accounts to buy currency in Fortnite.

Nintendo says on its Japanese support page that login information  was “obtained illegally by some means other than our service.” The company believe the hackers were able to do this by impersonating Nintendo Network IDs, the old login information used on the Wii U and 3DS. The hackers were then able to access users’ Nintendo accounts — used on the Switch and Nintendo‘s mobile games — via their associated NNIDs.