There was a thread earlier this year on that very topic:
https://mail.gnu.org/archive/html/lilypond-user/2021-06/msg00023.html
> On Jan 13, 2022, at 8:48 PM, Sam Gibson <samuelpgibso...@gmail.com> wrote:
>
>
> Good day.
>
> I wish to use the Nashville Number System, using numbers in place of chord
> names, for a simple lead sheet or chord chart. While it is possible to simply
> enter and position chords using \lyricmode, I do not know of a way to include
> the superscripts such as maj7 or sus4. Is there a way to use '\chords' and
> replace the letter chord names with numbers?
>
> I am entering chords in the following way:
>
> \version "2.22.1"
> \chords { c1 f:sus4 }
>
> I appreciate any assistance.
>
> Samuel Gibson
