Sunbreak hits 4 million, and the base game 11 million:

https://www.capcom.co.jp/ir/english/news/html/e220823.html

15mil for Rise is guaranteed.
Sadly we'll probably never get an update on the sales split, unless if it reaches 10mil on Switch someone at Capcom feels like reporting that.

I think it's a sure thing the NS version will hit 10m it was 8m back at the launch of the PC version and would likely be at around 9m now as we know it was doing around 200k a quarter and the release of Sunbreak would have boosted that last quarter as we know in Japan to date an extra 230k units were moved due to the physical version of Sunbreak being a set of Rise and the expansion.

On another note 11m ties Rise as Capcom's second best selling title in history.

Holy fuck!
Anyone know the platform breakdown?

Could this end up being the best selling third party software in Nintendo platform history?

It was at 7.7mil on Switch at the end of last year a few weeks before the PC version released. Like I said a few posts above your post, we will likely never get any further updates on that.

The highest selling third party game on a Nintendo console that we know the exact number of is Just Dance 3 on the Wii at 9.92mil. MHR can certainly top that, but Minecraft on the Switch has to be way higher than that already anyways.

This means that Sunbreak alone, counted as its own release, is in the top 20 highest selling Capcom titles ever, in less than two months.
Rise meanwhile is their third highest selling game ever.