If your iPod is not turning on, it may either have a bad logic board, a bad charging port, a bad battery, or water damage. There are many things that could make this happen. I would recommend taking this to the Apple Store. Also, make sure to plug it into your computer and open iTunes, try to restore it, put it in recovery mode.
There are many things that can cause the problem, and there are many things that can fix it. You should really get it diagnosed by a professional though.