This happens quite alot with mine. Usually happens because of not closing off apps and they have crashed which causes it to turn into black screen. As my home button is broke, what works with me is either leave the ipod for a few days depending how much charge it had in it and wait for the charging icon to appear, and then charge it, it should come back on. Or try charging it for an hour, see if the apple icon appears. The first idea i'd say is most useful.
If both your buttons work then hold them down together and apple icon should appear.