Corrupted files usually result from a bad download or a dying SD card. Try reformatting your SD card as FAT32 (not exFAT). exFAT is notorious for corruption on Switch.
However, the discussion of NSP files
is a major paid expansion that significantly builds upon the base game MONSTER HUNTER Portal New Content : Introduces Elgado Outpost as a new hub and the Monster Additions : Adds over 19 large monsters, including the "Three Lords": Master Rank (MR) Monster Hunter Rise Switch NSP UPDATE DLC