Nathan Donald Diazis an American mixed martial artist and professional boxer who is currently a free agent.
Diaz is most known for his time spent fighting in the Ultimate Fighting Championship (UFC), where he fought for over 15 years after winning The Ultimate Fighter 5. Prior to signing with the UFC, Diaz competed in World Extreme Cagefighting, Strikeforce, and Pancrase. Diaz has the third most UFC bonus awards, with 16 in total.
In 2012 he challenged for the UFC Lightweight Championship.