The Hatters boss has already pleaded guilty to misconduct following comments he made to and about referee Trevor Kettle following the 3-3 draw with Bradford on January 24.
Harford claimed that Kettle "shouldn't be refereeing at this level," and will now have a personal hearing on March 23.
Nicholls has been charged with inciting the crowd following the final whistle of that game, a charge he denies, and is to have his hearing held in the same week.
Source: Team_Talk