Any Remedies For Nail Biters?

We all have vices, bad habits that we would love to break but sometimes it's easier said than done. My little one bites his fingernails like crazy. I used to when I was his age and I would get in trouble for it all the time. My parents always threatened to put chile on my fingers, even though it never happened. 

Fyi the nasty tasting nail polish that is supposed to help keep your fingers out of your mouth, does not work. Been there, done that, it doesn't taste that bad, well to a nail biter anyway. lol Any other suggestions? Are you or do you know anyone who is a nail biter? Who do you get them to stop?