iOS 15
Show the iPod touch battery percentage
You can view how much charge remains in your iPod touch battery in the status bar. You can also add a widget to the Home Screen to monitor the battery levels of your iPod touch and connected accessories (including AirPods and other devices).
See the iPod touch battery percentage in the status bar
Go to Settings 
> Battery, then turn on Battery Percentage.
Add a Batteries widget to your Home Screen
Touch and hold the Home Screen background until the apps begin to jiggle.
Tap
at the top of the screen, then scroll down and tap Batteries.Swipe left and right through the widgets to view the size options.
The different sizes display different information.
When you see the size you want, tap Add Widget, then tap Done.