You can try connecting your iPod to your computer and opening iTunes. If your iPod is recognized, you can try to restore it to factory settings. This will erase all of the data on your iPod, but it will also remove the password. Then you can sync it back up with your computer and add back the data you want to keep.
If your iPod is not recognized by iTunes, you can try putting it into recovery mode. To do this, press and hold the Home button and the Power button at the same time for at least 10 seconds. When you see the Apple logo, release the Power button but keep holding the Home button. After a few seconds, you should see the recovery mode screen.
When your iPod is in recovery mode, you can connect it to your computer and open iTunes. iTunes should recognize your iPod and give you the option to restore it.
If you are unable to unlock your iPod using these steps, you may need to contact Apple support for further assistance.