Nia appears to be a legitimate cloud indexing/search skill, but it can upload local files, dependency manifests, and database connection/query data to Nia without strong warnings or confirmation.
Review before installing. Use this only if you are comfortable sending selected project files, manifests, saved context, and possible database credentials/query data to Nia. Avoid indexing folders with secrets, use least-privilege read-only database credentials, protect the API key file, and require explicit user approval before create, sync, from-db, preview-db, advisor, deps, context-save, delete, or rename commands.