Do not use Displex
It came out looking WORSE then before he used it. It may work ok for cellphone screens because the screen's plastic is harder but NOT for the iPod nano.
This iPod nano needs to be recalled IMHO. In Switzerland they are on display all scratched up but some stores are refusing to sell them. I purchased a Sony walkman instead of a iPod nano. They are really nice and don't scratch if you want an alternative.