An "other" that large usually indicates that the "other" included corrupted files. Usually restoring from backup eliminated the corrupted files. However, sometimes restoring to factory settings/new iPod is required.
To restore from backup see:
To restore to factory settings/new iPod see:
Also see this previous discussion:
Then backup and then restore from backup. See:
If you restore from iTunes backup all your synced media like apps and music have to be in your iTunes library since synced media is not included in the backup.