Otts, 46, was indicted July 21 and pleaded not guilty to possessing computers and storing images of child pornography that were shipped across state lines.
Chief U.S. District Judge Michael P. Mills will accept his plea in Oxford.
Otts faces up to 10 years in prison and a $250,000 fine.
Mills will decide his punishment after receiving a pre-sentence report from the U.S. Probation Service.