Obviously, it's not quite going to be what the iPhone or the iPod Touch is capable of if there ever is an iPhone Nano. I'm not saying there is but let's suppose one is in the world. We have to assume that it is.
Having said that, why am I bringing this up now? Basically, we're moving away from an one dimensional device, such as the MP3 player. For a while now, the iPod line has stopped being an MP3 player san the Shuffle. The Nano and the Classic as been a multimedia device for the long time, ever since it gained the ability to play simple games and, later, video files as well.
Now, the Nano has a feature. In case you missed it, Steve Jobs started off the "Let's Rock" even on September 9th and introduced this shopping seaon's new iPod lines. The Nano, now in its 5th generation, gained a new feature: video capture.
Not only that, the chip inside also has Wi-Fi capability though it isn't functional at this time. So, given the engineering feat that fit a small video capture camera in the Nano and the ever strinking package inside the Nano, it is possible that Apple can eventually add telephone function for the Nano as well.
Hence, the iPhone Nano. I'm not sure Apple will call it that but you get the picture. The iPod sales has been dropping as consumers take up the iPhone and the iPod Touches. Apple will continue to innovate and add features to the iPod line but it stands that if the iPod doesn't go away, Apple will move it closer to the iPhone with telephone function.
Furthermore, voice command will play a greater role in Apple mobile product. And given the limited input capability of the Nano, it is possible for Apple to circumvent this issue with voice command. Thinking voice dialing. If you've ever had to call customer services, chances are, you spend a lot of the time speaking to a computer. The technology already exists.
Another limit will be the small screen of the Nano. Apple can possible go multitouch with the Nano but let's face it, 2" screen? No way. If there is ever an iPhone Nano, I don't know how Apple will solve this issue or if it will at all.
Anyway, don't be surprise if Apple offers telephony to the iPod Nano. Stranger things have happened (like Apple leaving out the camera from the 3rd generation iPod Touch) and if Steve Jobs feels Apple can innovate in this direction, we just might see an iPhone Nano or and iPod Nano with telephony.