The chord generator is a quick way to break out of habits when coming up with song ideas on guitar or other polyphonic instruments. I made it so that I could write dozens of song ideas and think outside the box a bit, and it helped me write half the songs on my latest album.
It gives you a chord name to start on and then a set of + or - numbers. Those are your other chords, and you find them by simply moving up or down by that number of semitones (this is easier when you're playing barre chords, but it works well with conventional chord shapes if you know them).
The tempo is chosen for you too, but you can mute the metronome if you like.
Then all you have to do is repeat the chords for a minute or two while singing different melodies over the top until something works.
It's good to record yourself finding the idea because the process can become part of the song itself, not just the final idea.
If one set of chords doesn't produce anything, click again to generate new ones.
"Nice chord" means any chord you like the sound of.
Sometimes the worst sounding chords turn into the most interesting ideas.