I think Switch will end up right around DS '07 numbers, maybe slightly under right around 29 mil.
With BotW2 they could have broken 30 mil this year, but with seemingly only Pokemon as the mega selling holiday title, and considering two pokemons have already come out and this is a remake and another one is coming out two months later, I think Pokemon alone won't have quite enough kick to push Switch for sure over DS '07 numbers or to 30 mil.