This stands for Nintendo Submission Package , the standard file format for digital games and updates from the Nintendo eShop.
This is a modern overhaul of the classic 1995 strategy title, originally released on the SNES. Front Mission 1st Remake Review (Switch) | Backlog Battle FRONT MISSION 1st Remake (NSP)(eShop).part1.rar
Indicates this is a "dump" or copy of the digital version rather than a physical cartridge rip (which would be an .XCI file). This stands for Nintendo Submission Package , the