Updated through December 31, 2025! Really important that I just want to point out that I am counting all Switch 2 edition sales as Switch 1 software sales! I know it's different from how Nintendo tracks it, but fortunately this only impacts a very small number of games (for this list, Z-A will probably be the only major game impacted anyways).
There were several new position changes/additions this time around! MKWorld has burst onto the scene at 46th place. Expect it to continue to climb. For reference, MK8 DX sold 7.33 million by the end of 2017 and MKWii sold 13.67 million by the end of 2008! I'll be curious to see how MKWorld continues over time. I do expect it to at least be the third best selling Nintendo game of all time at the end of Switch 2's life. Whether or not it surpasses MK8DX & Wii Sports would remain up in the air, but I do see it at least exceeding 60 million. https://www.nintendo.co.jp/ir/pdf/2009/090130e.pdf https://www.nintendo.co.jp/ir/pdf/2018/180131_3e.pdf
SSBU has surpassed MKWii, becoming the 5th best selling Nintendo game. I could see it surpassing Super Mario Bro., but mostly if they do a Switch 2 edition (which I think is likely). If that happens then at the end of Switch 2's life, Super Mario Bros. will be out of the top 5! Mario Odyssey surpassed 30m and should definitely surpass NSMB & NSMBWii (I would say before the end of this year). Will probably just miss Wii Sports Resort in the end. SV surpasses Wii Play and continues the battle to 30m. I personally don't think it will make it, but we'll see. Even if it does, I don't see it passing RGB.
NSMBU DX, Switch Sports and Wonder continue their battle to 20m. I could honestly see all three getting there. Wonder will likely see a jump due to the Switch 2 edition. NSMBU DX will probably be around at least 19.50m by the end of this year. If Switch Sports gets a Switch 2 edition soon, that would help, but it probably doesn't need that to reach 20m. Combined, Z-A opened a hair below Arceus, but we'll see what happens. Will probably at least cross 15-16m lifetime.
Jamboree is less than 1m from joining this club!
