Unless the Switch is undertracked and has a really strong holiday it seems a done deal at this point it'll be down from 2020. However it'll have a 2nd year in a row that's better than the Wii's best year so still extremely impressive.
Personally, I think that this Q3 FY will be around 5.75 (because of early shipments of OLED in time for launch, but also because it's tracking significantly higher than 2019 which was at 4.8M).
If this is the case then Nintendo would need about 12.5M consoles shipped in Q4 for it to exceed FY 2020. Is it possible? Maybe...is it likely? Probably not. Unless Q3 is higher than I anticipate then Nintendo is going to be slightly down, likely by around 1M units. I guess we will find out soon.