If your iPod is locked with forgotten or forgot password, you must find the password or clear the password before you can use it again. So at first, I need to know what the password is.
1. If the screen lock password is lost, you may need to reset your iPod to factory settings to clear the password. Be aware that iPod factory reset will clear the settings and personal information as well as the lock password. So remember to backup iPod before factory reset.
2. If the iTunes backup password is lost, you can't restore iPhone from backup anymore. So you need to find the password to unlock the encrypted backup.