Just got my nano. It's very, very small and egg-shaped (so cute). I didn't get a chibi so I can't really make a comparison. But it has no icons and no status screen. You press A button and you're taken to a screen that I assume says "food" and "play". In the food screen, as per usual you have a choice of a meal and a lolly. The only game that I can play at the moment is one where you catch falling letters, matching the one that is displayed. I don't know if you'll get more games in later stages of evolution. Not entirely sure how to check it's status, but you can press the C button and your character comes up to the screen and makes a happy face (don't know whether it does that all the time or if its indicative of its mood, etc). The screen is clear and easy to see, unlike the chibi (I used my friends' once and found it hard to see). It's cute but if you haven't ordered yours yet I'd probably wait for the price to drop a little, doesn't really seem worth $30.
Update: The nano does poop, you just press A to flush it. And pressing C does show you it's mood, by little bub seems to be upset with me at the moment! Gotta go play with her now!
Edited by bubblemuffin, 27 October 2010 - 12:44 AM.