Brad Bannon, a lawyer for David Evans, said that motion would request that the court sanction Nifong with fines and contempt of court.
Nifong could also face civil lawsuits; Bannon's partner Joe Cheshire said on Friday that he expects "extensive civil action."
Lawyers are also pushing for an independent federal investigation into Nifong's conduct.
The mood at the trial Saturday was a remarkable reversal of the courtroom atmosphere in the early days of the case. Then, the parents of the players sat wide-eyed and stone-faced, occasionally shedding a tear, while the now-disgraced prosecutor moved through the court room smiling and navigated the camera crews outside in the hallway with a grin on his face.
Saturday, Nifong and his wife wept during a recess and held each other, clearly shaken, while the players and their families smiled and chatted with easily with one another.
As the first witness to testify in the penalty phase, David Evans Sr., whose son Dave was charged, described being "floored" when he heard Nifong tell the media that the players were not cooperating fully with the investigation.
He described how his family learned of his son's indictment on Dave's graduation day, and testified that his son's job offer from the Wall Street firm J.P. Morgan was withdrawn after the charges were brought. He said he recently "Googled" the phrases "Dave Evans" and "Duke Lacrosse," and that the search turned up more than five million hits.
Evans said his son and the other players "stepped up to the plate'' and cooperated fully with investigators. He said that Nifong has now acknowledged he "crossed the line'' of ethical conduct and "maligned an entire team -- 47 players, their parents, their grandparents.''
David Evans Jr.'s grandfather on his mother's side died of a heart attack last August before the charges were dropped, Evans Sr. said.
"It was very very hard on him,'' Evans Sr. testified. "He took it very, very hard. He couldn't understand. He was consumed with the case. As it moved along he would call several times a day. He'd say, 'Why is this district attorney going forward? Look at all this information? The accuser is not credible. Why isn't the system working?'
"Our great regret is that [the grandfather] died before the system worked," Evans Sr. said, "before he was found innocent."
In a statement that seemed to both echo and mock Nifong's tearful claim Friday that the case will be associated with him until he goes to his grave, David Evans Sr. told the court that his son, too, "believes that when he dies, people will say he was one of the three Duke lacrosse players who was accused of rape."
Next up was Colin Finnerty's mother Mary Ellen Finnerty, who said that after 26 years as a parent, learning her son was indicted for rape and kidnapping was "the hardest moment as a mother I have ever had."
"We were in the fight of our lives,'' she said. "We now had to fight to save our son's life. From that day on that was our job as parents. How do you explain to a 10-year-old that her brother has been indicted for rape?'' she asked rhetorically.
When her son's name was finally cleared in the wake of an investigation by North Carolina State Attorney General Roy Cooper, "it was an answer to all our prayers," she said.
"Nobody can give the families back the 14 months we've gone through,'' she said, and began to cry. "Laying in bed at night and saying that they could go to jail for 30 years for a crime they didn't do."