Amazon UK has listings of several Switch titles (Possibly 30) stating source being peculiar “Nintendo Switch event” & inside the leak includes 2 Pokemon 3DS titles for Switch. Could be old/ mistake/ error, & it could mean a Nintendo Direct is coming soon with several announcements therein, Retailers (especially the big ones like Amazon) often have advance info to prepare promotions and pre-orders. Amazon did something similar several months back where they put up placeholders for a ND.
With mainline PKMN software hitting the console next year it would be safe to assume Nintendo aims to fill the void between using a series of ports bringing 3DS fan base to the big screen via ports of select handheld releases familiar to gamers gearing them up for a intended larger and needless to say successful launch of the upcoming Lets Go iterations hitting Switch 2019.
Pokemon Go Was #1 Top Grossing Mobile Software July 2018 in US, #4 World Wide