Hey, I think your question belongs in the
Which One Should I Buy? forum.
The older Nooks did not support an expandable TOC and I don't believe the newer ones do. Kobos all run essentially the same software and do not have expandable TOC. Not sure about Kindles.
Some people put an alternate reader on their Kobos and Kindles,
KOReader. I don't know what that supports as I've never tried it.
You might look into an e-reader that runs Android. Then you could install Moonreader on it. The one I've looked at is the
Icarus Illumina HD. But there are several others.
Depending on where you live, ordering one could be a pain (they are mainly sold in Europe).