The Switch 2 comes with 256 gigabytes of built-in storage, which is eight times more than the 32 gigabytes found in the original Switch. Furthermore, the games seem pleasantly small, at least from Nintendo themselves, so it looks like you might not need to upgrade.
But how much does a Switch 2 cartridge hold at most then? Well, CD Projekt Red's community manager has now answered that in a BeatEmUps video (via Resetera), where he can be heard saying:
"We specifically went for the highest capacity, so 64 gigs."
Games can get bigger than that as there are digital downloads, plus it's already been confirmed that some Switch titles only have blank cartridges that act as a sort of key that lets you download the games. But when it comes to physical releases, at least for now, it seems that 64 gigabytes is the ceiling.