The Legend of Zelda: Tears of the Kingdom also moves up the rankings, overtaking Super Mario Party to reach eighth place.
As of June 30 earlier this year, the kart racing phenomenon's worldwide sales stand at 62.9 million units, as per figures released by Nintendo.
The Legend of Zelda: Tears of the Kingdom has also reached 20.80 million units sold since launching last year for Nintendo Switch.
Along with its Wii U version, Nintendo's acclaimed kart racer has sold 70.43 million units since first launching in 2014.
Combined with the sales of its original Wii U version, the kart racer has now sold a total of 69 million units.
Meanwhile, Super Smash Bros. Ultimate sits at 32.44 million units sold, while The Legend of Zelda: Breath of the Wild sits at 31.15 million.
Booster Course Pass - Wave 6 will add eight new tracks and four new characters to the kart racer.
Recent reports indicate that a new bundle for the Nintendo Switch OLED is on its way just in time for Holiday season.
Famitsu's newest sales chart for September shows Nintendo dominating game sales, followed by FromSoftware.
In addition to eight new tracks, the kart racer's final DLC drop will also add four new racers with Diddy Kong, Funky Kong, Pauline, and Peachette.
NBA 2K24 debuted in the charts at seventh place, while Fae Farm ranked ninth. Crime Boss: Rockay City managed 22nd place.
Meanwhile, Animal Crossing: New Horizons stands at 42.79 million units sold, while Super Smash Bros. Ultimate has risen to 31.77 million units.
The kart racer's penultimate DLC drop will add eight new courses and three returning courses to its ever-growing offerings.
Among the eight new tracks being added with Wave 5, one will be a brand new track, while three characters are also being added.
Nintendo says the kart racer's penultimate DLC launch is not far away now- though a release date remains unannounced.
Animal Crossing: New Horizons remains in second place, with 42.21 million sales in the three months ending March 31st, 2023.
Mario Kart 8 Deluxe, Super Mario Odyssey, and New Super Mario Bros. U Deluxe all find themselves in the top 10 thanks to sales boosts.
Super Mario Odyssey on Nintendo Switch also saw a nice increase from 13th to ninth place, likely due to the ongoing MAR10 day sales.
The kart racer's latest DLC update added five blank slots to the character selection screen, suggestion more additions are on the way.
Wave 4 will add eight new tracks to the kart racer, one of which – Yoshi's Island – will be an entirely new track.
