Yes that is a good idea to teach chords. To add this feature I think the best way is to just create some midi music that teach chords.
I think the best way to learn this is to play a cord of C major made up of just three notes C E G (these three notes are called a chord triad) then play a chord of F major (that has the note F A C) followed by G major (which has the notes G B D). These three chords (C followed by F and then by the G chord) is called the three chord trick. see this page for more info https://www.harmony.org.uk/book/pop_and_rock_music_three_chord_trick.htm.
Is this the type of thing that you would like to learn and practice? if so I'll knock up some midi files that work with PianoBooster that teach these technique and gradually gets more advanced.
Hi Louis i have been teaching keyboard via your program and a similar one on android piano note trainer to some syrian refugees here in Turkey. I myself am not so skilled but can play notes in our local church. So many of the songs only have chord charts.