In Reaper Menu > Actions > Show Action List > Reascript > New
copy and paste code below,
select a track from the imported musicxml
in the Reascript window > Ctrl+S to save and run script
close script window
to run the script next time just type the name you save it to in the filter box
in the midi editor File > Export to New MIDI file
Biab File > Import > Import Melody from MIDI file.
You can also import the Midi from Biab into Reaper and copy the BB Chord Track Midi notes to any one of the musicxml track replacing the existing notes, this will give you a BB Chord Track as well as Chord Lyrics.

Code:
reaper.Undo_BeginBlock2(0)
reaper.Main_OnCommand(40421,0) --Item: Select all items in track 40421
reaper.Main_OnCommand(40153,0) --Item: Open in built-in MIDI editor (set default behavior in preferences) 40153
take = reaper.MIDIEditor_GetTake(reaper.MIDIEditor_GetActive())
reaper.MIDI_Sort(take)
MIDIOK, MIDI = reaper.MIDI_GetAllEvts(take, "")
tChords = {}
stringPos, ticks = 1, 0
while stringPos < MIDI:len() do
    offset, flags, msg, stringPos = string.unpack("i4Bs4", MIDI, stringPos)
    ticks = ticks + offset
    if msg:byte(1) == 0xFF then
        chord = msg:match("text (.+)")
        if chord then
            tChords[#tChords+1] = {chord = chord, ticks = ticks}
        end
    end
end

for i = 1, #tChords-1 do
    
    reaper.MIDI_InsertTextSysexEvt(take, true, false, tChords[i].ticks, 5, tChords[i].chord)
     
end
reaper.Undo_EndBlock2(0, "Convert Notation Event Text to Text Events", -1)



Or in Karakan select the BB Chord Output track, (you can add bar numbers or bar characters with the chords, just join them so there are no spaces \1.|Bm|\2. \3.|Em|\4. or |Bm///|//// |Em///|//// or ??? )


Attached Files (Click to download or enlarge) (Only available when you are logged in)
KK-Chords.gif (262.68 KB, 309 downloads)
Reaper-NotationEvents-to-TextEvents.png (19.09 KB, 160 downloads)