This works from a midi chord track.
Biab will create a midi chord track that you save then import back into Biab.
The ChordPosition plugin has it's own sound but it can send midi out to your Virtual Instrument (though you will need to use MiniHost to send it out as Biab has no midi chain)

So in Win In BB > Prefs > Chord Output

Save to MID > File on Disk

File > Import > Import Melody from MIDI file (import the same channel you set in the Output Chords dialog)
load the ChordPosition plugin on the Melody track.

For the Mac set the Chord Output see below.
click the MID button > File on disk to save to save the BB Chord Output to a track in the midi file.

Free Biab & BiabVST Chord Picker Tool (look at the bottom of the page for the latest version.)