Zero and none -- those are the chances Tenshin Nasukawa has to beat Floyd Mayweather when they square off on New Year's Eve ... according to Roy Jones Jr.
"He's not gonna lose the fight."
Floyd and Tenshin -- an undefeated 20-year-old kickboxing superstar -- are fighting in Japan at the end of the month ... and there are some people who think Tenshin could be the guy to finally put Mayweather on the canvas.
Roy Jones, however, is not one of those people.