From Wikipedia, the free encyclopedia. Nicholas Robert Diaz (born August 2, 1983) is an American professional mixed martial artist. He is the current Strikeforce Welterweight Champion and former WEC and IFC Welterweight Champion. He has competed in the Ultimate Fighting Championship, Pride Fighting Championships and Elite Xtreme Combat. Diaz was promoted to black belt in Brazilian Jiu-Jitsu by Cesar Gracie on May 8, 2007. Diaz trains at Cesar Gracie Jiu-Jitsu Academy in Pleasant Hill, California. He holds notable wins over Frank Shamrock, Robbie Lawler, KJ Noons, Hayato Sakurai, Chris Lytle, and Paul Daley. He is currently ranked the #6 welterweight in the world by Sherdog, #5 by MMA Weekly, and #8 by USA Today. Description above from the Wikipedia article Nick Diaz, licensed under CC-BY-SA, full list of contributors on Wikipedia.