[KevinH]

Sigil does not default to "hiding" the nav from the reader. Sigil assumes that setting linear="no" is enough for real epub3 readers but not all follow that part of the spec.

So to do this inside Sigil requires manually editing the nav and manually editing the opf as the very last step.

In the nav landmarks section you remove the epub-type toc link that points to the nav itself.

In the opf, you remove the nav's entry from the spine.

This must be done last thing before saving to prevent Sigil from reverting things the next time is rebuilds the opf.

The nav will still show in Sigil's BookBrowser but will not show in the e-reader as a "text chapter" and will only show via the TOC just like the ncx.

FYI, The spec states the nav itself can only link to resources listed in the spine. If you manually remove the nav from the spine, then the nav can't link to itself, or it violates the spec.