I purchased a non-working Tamagotchi Nano with the intention of making it work again, but when I got it, I quickly realized it's not set up the same way as the newer minis, or even any other regular Tamagotchi. I looked up how to take it apart and there is absolutely no information anywhere, but I have figured it out! Sorta.
When you take the battery cover off, there are two screws that hold the casing on the bottom half, but there's two more screws hidden under the plastic shapes on either side of the speaker holes. I had to rough up my (broken) nano a bit to work those out, and I did damage the plastic some. I'm not sure how to safely take those plastic parts out just yet, I'm sure there's a tool for them, but I'm not sure what the plastic parts are even called, I guess they're just tiny protective covers.
Anyway, I just thought I'd make this post to potentially help anyone who is needing to take their Nano apart, feel free to discuss ideas about safely removing the plastic parts.
Pics here: https://drive.google.com/folderview?id=13rtUGSfBPqY8g3u-VYh-R8KMRp5pYHXI
The clock and capacitor definitely need to be replaced