That makes it the third-best-selling console of all time.
Analysts predicted last week that Nintendo could score record early sales with the Switch 2 - but it remains to be seen if it can match the performance of its predecessor.
Challenges for Nintendo include uncertainty over United States trade tariffs and whether it can convince enough people to pay the high price for its new device.
The Switch 2 costs $449.99 ($745) in the United States, compared to a launch price of $299.99 ($495) for the original Switch.
Both are hybrid consoles which can connect to a TV or be played on the go.
New games such as Donkey Kong Bananza and Mario Kart World - which allow players to go exploring off-grid - are also more expensive than existing Switch titles.
Nintendo forecasts it will sell 15 million Switch 2 consoles in the current financial year, roughly equal to the original in the same period after its release. The Switch 2 “is priced relatively high” compared to its predecessor, so it “will not be easy” to keep initial momentum going, the company’s president Shuntaro Furukawa said at a financial results briefing in May.
The Switch 2 has eight times the memory of the first Switch, and its controllers, which attach with magnets, can also be used like a desktop computer mouse.
New functions allowing users to chat as they play online and temporarily share games with friends could also be a big draw for young audiences used to watching game streamers.
Success is crucial for Nintendo: while the Super Mario maker is diversifying into theme parks and hit movies, around 90% of its revenue still comes from the Switch business, analysts say.
- Agence France-Presse