She had previously pleaded not guilty, and today's guilty pleas were entered at a pre-trial call-over.
Judge Raoul Neave remanded her on continued electronically monitored bail for sentencing on June 21. He ordered a pre-sentence report by Probation, and a psychiatric report. She will be assessed for a possible home detention or community detention sentence.
Watts has previously been convicted of charges of making a false statement, breaching a protection order, and perverting the course of justice, relating to a former partner.
The new charges related to a woman with links to her former partner. That woman, who alleged ongoing harassment by Watts, took out a protection order against her.
Between January and August 2021, Watts sent a letter addressed to the woman, in the name of a fellow inmate at Christchurch Women's Prison. The letter said Watts had evidence against the woman on her "burner phone" and threatened to go the police if she did not admit offending.
In September 2021, police received a letter sent from Christchurch Women's Prison. They approached the purported letter writer - an inmate - who showed them other letters which had been "returned to sender".
One letter, purported to be signed by the woman who alleges harassment by Watts, said that she had supplied methamphetamine, and gained access to Watts' social media accounts, driver's licence, and medical records.
The second letter, purportedly signed by the same woman, admitted similar offending and said, "I wanted to drown Nicola in the river".
After her release from prison, Watts put in the Crimestoppers report, again in the name of the other woman, and giving her email address. The report requested that the woman herself be charged with all the offences that Watts is facing.
The woman has confirmed she did not write the letters or the Crimestoppers reports. "She is frustrated and distressed by Watts' actions, which are impacting on both her work and her home life," the Crown told the court. "Watts is trying to transfer all the responsibility for the offending on to the victim in this matter."