I have exactly the same problem with the on/off switch on my nano 6 gen.
I don't understand why you say it has been out for less than a year??? I got my nano 6th gen at the beginning of 2012, that's 4 years ago! I got it as a result of the recall/replacement of the incendiary nano 2nd gen. So in place of a defect, I was given another defect!
I don't think Apple will replace, despite the fact that it's clearly a design fault and a common problem.