In essence, the iPod Touch6 can be regarded as a simplified version of the iPhone, except that there is no telephone, cellular data network module and built-in compass software, and other functions are basically the same as the iPhone.
IPod nano7 is just a video+audio mixed multimedia player, which has no functions such as taking photos, playing games and making phone calls, so it can't be compared with iPod Touch6, and its practicability is low.