Required downloads on Switch for games you buy on a cartridge isn't anything unusual anymore and some of them has been really big. One of the worst offenders was WWE 2K18 which forced you to download 24GB despite the fact that everything needed should have been on the cartridge, after all, that's why you buy a game on cartridge as opposed to a digital download.
Thanks to Amazon, we now know that Starlink: Battle for Atlas also has a required download, which is 4GB. That is not too bad, but considering the hybrid console only has 32GB built-in memory - it is still something to consider that you should know about before making an investment.
The Switch version of the game is a bit special as it includes Fox McCloud as a guest character, and is widely believed to be the most popular edition.