I don't actually have a saw with a nib so I can't experiment, but if I did I would give two things a try to see if they amount to anything. I would try the idea of using the nib as a nicker to create a starting point for the saw cut by holding the saw upside down(teeth up) and running the backedge of the saw along side my thumb and drawing back the saw to nick the corner and create the starting point. This would produce a slight roundover that would seem to make starting a cut simpler.
Also, I am now thinking, since the nicker idea doesn't seem to be flying, is that the nib might be a simple way, coupled with a straightedge, to simply scribe a line on the board for the intended cutting line. Use the same tool to mark the line and then cut it. Who knows, it just might work?