A couple of days ago, the Nintendo Switch Online was released via the eShop and will serve as the console’s online subscription service. The service hasn’t even reached one week since it went live and modes have already hacked it. A modder named KapuccinoHeck revealed that a hacked Switch can allow players to easily load their own NES ROMs and play via the Switch Online’s NES emulator.
KapuccinoHeck explained on Twitter that the Switch Online app treats NES games as plain .nesfiles, and stores them in a database. Given this, it is easy to manipulate the database and add other NES games if the 20 titles that were made available by Nintendo is not enough for you. KappuccinoHeck revealed the process in a video where they loaded Kirby’s Adventure on the Switch.
Of course, hacking your Switch is a delicate process that may damage your console in the long run. Furthermore, Nintendo may detect this and permanently ban your account so doing this hack is not at all advisable.