Nested TOCs?

Is there anyway to export the ebook with nested TOC’s? I’m working on a rather large project for Amazon and a flat TOC is going to be rather awkward.

Custom TOCs aren’t currently possible from Scivener, so you’ll need to tweak it in something like Sigil after compiling to epub. From there you can use Amazon’s Kindle Previewer (or KindleGen directly if you’re comfortable running through the command line) to convert it to mobi.