Navigate to the location of the update NSP file, select it, and choose to install it to either the NAND (internal storage) or SD card, depending on where your base game resides.
While there is no update file currently floating in the ecosystem, it is useful to know what a future update (if released) would likely target: tomb raider iiii remastered switch nsp update
“This build was archived July 22, 1999. Core Design build 408. Pre-publisher review. They cut the level ‘The Necropolis of the Ancients’ because the PS1 couldn’t render the 17th room. But the room was never empty. It contained a single NPC — a girl in a brown jacket. She asked: ‘Why do you keep coming back?’ If you answered ‘Because I forgot,’ she would give you the Iris. If you answered ‘Because I need to remember,’ she would vanish. Both answers were cut. The devs said it broke the fourth wall too hard. But the wall was already broken. They just glued it with silence.” Navigate to the location of the update NSP