Wii discs typically contain "update partitions"—data used by the original console to update its system software. NKit strips these to save space but keeps a record of what was removed.
For the core application without the large partition files, you can visit the official Nanook/NKit GitHub repository . How to Use NKit 1.4 for Recovery Download Nkit 1.4 Wii Partitions
For more information on Nkit 1.4 and Wii game partitions, check out the following resources: Download Nkit 1.4 Wii Partitions
that includes the necessary recovery data to restore compressed or "scrubbed" Wii disc images back to their original, byte-for-byte -verified ISO state Overview of NKit Download Nkit 1.4 Wii Partitions