It depends how much stock they have tbh but i don't see it crossing a million. I feel like 700-800k would be an amazing launch for a model that isn't so groundbreaking. Metroid Dread might help a bit too since some fans of the franchise or genre might not have a Switch just yet.
It will for sure boost the sales over the rest of the year tho. It can retake it's lead over 2020 imo.