The Houston Chronicle first reported the booking, which was subsequently confirmed by UFC officials on Monday.
The announcement comes just days after Cormier (12-0) lobbied hard for the bout on Twitter, drawing up a fake contract and imploring Nelson (19-8) to re-sign with the UFC. Nelson ultimately elected to do so, first signing the fake contract then repeating the process with Zuffa officials.
Due to Cormier's reluctance to fight AKA training partner Cain Velasquez, the bout may potentially serve as his last at heavyweight, a division where the undefeated former Olympian has racked up an impressive hit-list consisting of Antonio "Bigfoot" Silva, Josh Barnett and Frank Mir, among others.
UFC 166 takes place October 19, 2013 at the Toyota Center in Houston, Texas. UFC heavyweight champion Cain Velasquez battles No. 1 contender Junior dos Santos in the night's main event.
UFC 166 fight card:
- Cain Velasquez vs. Junior dos Santos
- Daniel Cormier vs. Roy Nelson
- Nate Marquardt vs. Hector Lombard
- Diego Sanchez vs. Gilbert Melendez
- Tony Ferguson vs. Mike Rio