Check out the above chart. It’s no secret iPod sales had steadied, or even dropped a bit over the last couple years. Still, it’s generally believed a lot of that is due to people buying iPhones, which are iPods that don’t show up in these sales figures.
In any case, look at the first two months of the last three years. From Y/Y of -28 and -13 to +5 in January, and from -5 and -16 to +10 in February. While the iPod nano may have some hand in this, the iPod touch is clearly selling very well.