Announced DLC for Scarlet/Violet for Fall 2023 and Winter 2023. Also announced a Detective Pikachu sequel for October 2023. Knows of no other games currently in the works for the Switch. Personally expects a Black/White remake in Fall 2024. (Loves releasing stuff in November, but not always.) Might surprise everyone with something else in the meantime too, like Virtual Console releases or a new spin-off.
Doubts a new generation on the Switch, however. Produces a new generation every 3-4 years. Released the Switch 6 years ago. Usually produces a new console every 6 years. (Goes a little longer for handhelds.) Already lived as long a life as most consoles do.
Or do you mean Pokemon games at all, on any system? Sold 22.1 million copies of Scarlet/Violet as of a few months ago. Ranks 7th among all Switch games. Consistently sells well too, with five Pokemon games in the top 13. Will not end the series there.