That print solution doesn't sound like you would end up with an actual a TXT file.

Maybe using MusicXML you figure a way to get it to txt. (?)

Otherwise I'd just type it out.
I haven't heard many requests for a TXT file end result.
If you just want a printout you could screen shot the resulting chords and print that.

What is the intended purpose of the txt file?
Or is a printout all you were after to begin with?

I do not work here, but the benefits are still awesome
Make your sound your own!