Michael John Nickels (born December 13, 1971) is an American mixed martial arts fighter who formerly fought in the promotion Ring of Fire. He was also a contestant on season 3 of The Ultimate Fighter, training under Ken Shamrock and is a purple belt in Machado jiu-jitsu. He is heavily tattooed and runs a tattoo parlor, Twisted Sol, in Denver, Colorado.

Nickels competed in Ring of Fire from September 2004 to September 2005, earning 3 wins and 1 loss. In 2006, Nickels participated in the third season of The Ultimate Fighter. He lost in his first fight to Matt Hamill by unanimous decision; however, he returned on the undercard for the finale, defeating previously undefeated Wes Combs by rear naked choke in the first round.

Nickels lost his fight against Stephan Bonnar at UFC 73.

In April 2005, Nickels won a gold medal at the Pan American Brazilian jiu-jitsu championships. He went on to win a gold medal at both Grapplers Quest Nevada (November 2005) and at the Shawn Ray 1st Annual Submission Grappling Classic (May 2006).

Currently, "Big Mike" is training for the Ring of Fire taking place in Denver Colorado on June 13, 2008. In addition to his heavy training schedule, he is an instructor at Colorado Brazilian Jiu-Jitsu Academy in Highlands Ranch Colorado along with Machado jiu-jitsu black belt and Helio Gracie trained David Ruiz. He is a tremendous instructor and one of the most feared fighters in all of Colorado. Mike also won his last fight against Vladimir Vuckovic at Ring of Fire 32 on June 13th 2008 via rear naked choke in the 1st round.