He reportedly sent thousands of messages across multiple platforms to underage girls using the Whisper App.
They said an undercover officer posed as a minor, which led to his arrest in August 2023.
Under Thursday's plea agreement, Shores pleaded guilty to one count of attempting to produce child pornography, while six other counts were dismissed.
He will serve 15-20 years in prison, and the court may require him to pay restitution to the victims.