I'm unable to sync my iPod nano to iTunes

Select the iPod icon once it appears at the top of the iTunes window:

That will display the Device/Settings/Summary pane. Using the screenshot below as your guide, switch to the Device/Settings/Music pane (1.):

• select the Sync Music box (2.) so that there is a tick (checkmark) in it
• select the Entire music library button (so there is a dark mark in the button). This adds all selected content in your music library. Note that with this option, you will not see the sections numbered 4 in the screenshot
• tap the Sync (or Apply) button in the lower right corner of the iTunes window (not shown in the screenshot)
• once the sync has finished, safely eject the iPod (tap the eject icon next to the iPod icon):

Note that my screenshot shows two iPods, wirelessly connected.

LW2221 wrote:

I am unable to sync my new iPod to my downloaded iTunes.

What happens when you try?

I assume that you have set Sync options for this new (to you) iPod. Each device has to have Sync options set for it alone, so settings for the old iPod will not work with the new one.

LW2221 wrote:

Will this work for my iPhone 14 or my iPad mini 6?

Yes, it will. Each device is set up separately from any other.