My iPod nano turned off, won't charge and now is making ticking noise.

While Flash storage is more rugged from bangs and drops over mechanical hard drives. They to have a weakness!

Just like a piece of paper there’s a limit on how many times you can tear it up. Here it’s the number or writes a given cell can be written to. While your songs maybe stable just the act of use still creates change and give the age and your use it’s possible the flash are gotten worn.

But your issue could be different here. Which gets into repairability of the unit and the cost of the repair.

@slendieusz sound like a power issue. You will need to replace teh battery and while you are at it check the coils for your backlight. You also want to check your dock connector. Check for corrosion as well as bend/broken pins. Your iPod is not getting the power it needs to turn on. Schematics etc are NOT available.

Those are a beast to work on, but with patience you may just be able to resurrect it. To work on it use the guides from here iPod Nano 4th Generation . Check the iFixit Wiki iPod Nano 4th Generation Troubleshooting and see if that help to diagnose this a bit better before tearing it down.