https://www.pgmusic.com/forums/ubbthreads.php?ubb=showflat&Number=460110#Post460110

This will give you basic import Biab/RB chords to REAPER,
if you add the 2 scripts together in a new Action it will do it in one hit. So you will have the chords in the regions and as a track with text items, you can also just have the regions or just the text item track.
So just drag the exported music xml into the REAPER track and run the Action. If you need the part makers, save the bb song to Midi, in Options dialog enable Part Marker saving, now drag that midi into REAPER importing the markers. You can delete the midi tracks after you have got the info out of them.