The file Cuphead [romstorage.com].nsp is a Nintendo Submission Package, which acts as a standard digital format for installing games via custom firmware on a Nintendo Switch console. Sourced from a third-party, this file requires installation tools like Goldleaf or USB-based methods such as DBI to manage potential FAT32 file size limits, while carrying significant risks of malware, file corruption, and Nintendo network bans. For guidance on installing NSP files, see this YouTube video .