Philadelphia owned a 14-point lead at halftime, and then collapsed over the final two quarters. The 76ers managed just eight points in the third period and 24 during the second half.
Nowitzki scored 24 of his 28 points after the break and also grabbed 12 rebounds. Dominique Jones, who had appeared in just 16 games this season prior to Friday, scored 12 points to make up for a shortage of backcourt players.
Dallas was without Jason Terry (personal reasons) and Delonte West (broken right ring finger).
The comeback gave the Mavericks their sixth straight win, which they achieved while making only 38 percent of their shots from the field. Philadelphia was good on just 33 percent and hit 1-of-14 from 3-point range.
Nikola Vucevic led Philadelphia with 16 points. The 76ers have lost three straight home games, something that had not happened in two years.