Thank you. First in Finder use the menu option Finder > Settings > Sidebar and make sure there is a tick against CDs, DVDs and iOS Devices. You should now find the iPod shows up once or twice in the sidebar, once with an iPod icon, and again with a generic disk icon if disk use is enabled. Select the first one and click into the name of the device just next to the image of it. This is an editable field.

When I've tried renaming my iPod the second entry, which is all in caps, didn't change automatically. It may be best to right click on this entry, click rename, and then type in the chosen name which will be converted to all caps, and may drop certain characters, just to remain consistent with how things used to work.
tt2