any computer sequencer worth it's salt will convert a midi track into a score and print it out nowadays. There are many ways to do it, for lead sheet just save the melody as a midi, type in the chords and print - you could make a full midi on the KN and then print a multi instrument 8 or 16 stave arrangement, rather quicker I find is just to play the KN sequencer into the computer and then print a multi stave arrangement.

It's even been known to then put the score in the KN screen