Before diving into Celeste specifically, it is helpful to understand what an NSP file is.
The crown jewel of the update. Farewell is a gargantuan epilogue chapter that takes place after the main story. It contains over 100 new screens, new mechanics (like jellyfish parachutes and pufferfish explosions), and a difficulty curve that surpasses the C-Sides. This chapter is notorious for requiring the player to have already completed all B-Sides to finish it. Celeste Switch NSP -UPDATE- -eShop-
Celeste is a relatively small game, requiring approximately 1.5GB of space, but updates may require extra room 1.2.1 . Before diving into Celeste specifically, it is helpful