If your base NSP is irreparably damaged but you have a working update NSP for the same game ID, some advanced tools can attempt to the Program NCA from the update (rare but possible with hactool and Python scripts). However, in 99% of cases, it is faster to obtain a clean base NSP.
Encountering the error: "The NSP file is missing a ProgramType NCA"? You are not alone. the nsp file is missing a programtype nca fix
If this guide helped you, consider bookmarking it for future reference. And always remember: keep your prod.keys up to date! If your base NSP is irreparably damaged but