If you’re referring to the Lyrics/Chords extension that I recently released, then yes, it does support piano chord diagram e.g.
This is the format of the directive:
{define: D keys 0 4 7}
This is taken from the ChordPro.org site:
Chords in the root position always start with note 0 . The first inversion starts with 4 (major) or 3 (minor) third. The second inversion starts with the fifth 7. Note that keys that would exceed the diagram are silently wrapped.