Really good match up, I think team DS takes it
I think it's not even dependent on how much Nintendo can sell, but rather how much they can produce, with several parts being in critical supply with the current chip crunch.
As such, my take is: If the chip crunch eases fast enough, the Switch will win. If not, the DS will prevail.
The Nintendo eShop rating Thread: http://gamrconnect.vgchartz.com/thread.php?id=237454
The Steam/GOG key gifting thread: https://gamrconnect.vgchartz.com/thread/242024/the-steamgog-key-gifting-thread/1/