The Bobcats lost their 17th in a row, their last victory having come over Washington on Nov. 24 in a game that went double overtime.
Johnson lost his job after the Nets had lost 10 out of 13 games following an 11-4 start to the campaign. His dismissal followed his being named Eastern Conference coach of the month in November.
The Nets rushed to an 18-point lead after one period with Lopez eventually scoring 26 points along with 11 rebounds. Deron Williams had 19 points and Joe Johnson chipped in 16. Reggie Evans came off the bench to grab 17 rebounds.
Charlotte was led by 13 points from Hakin Warrick and 12 from Ramon Sessions.