Nintendo have announced that since the release of Super Smash Bros. Ultimate, the Nintendo Switch has taken first place as the "fastest-selling US console."
The announcement is sourced from Destructoid, as well as the above Twitter post which comes from the Nintendo America Twitter page. According to communication between Nintendo and Destructoid, the Nintendo Switch from March 2017 to November 2018 has sold "more than 8.7 million units" making it the "fastest-selling US console."
Furthermore, Nintendo also say that the Nintendo Switch "outpaces US sales of all other current-generation systems at the same point in their life cycles." Judging by the sales Nintendo are putting out moving closer to the festive season, we can assume these numbers are only going to get better over the course of Christmas and the Boxing Day sales. My curiosity has been spiked with this question I gave to myself, "what first-party Nintendo games will push Switch sales in 2019 as much as Super Smash Bros. Ultimate has? "