The Wizards, the Eastern Conference's worst team at 14-49, led by 10 points in the first half before the Mavericks (38-25) rallied to tie it at halftime.
Nowitzki had nine rebounds and a season-high seven assists, and Antoine Wright scored 16 points for Dallas, which was playing without Josh Howard. The Mavericks' starting forward has a sprained left ankle.
Antawn Jamison scored 24 points and grabbed 11 rebounds for the Wizards, who dropped to 4-27 on the road.
Washington forward Caron Butler returned to the starting lineup and scored 20 points after missing three games with a strained left hamstring.
The Wizards shot 52.7 percent from the field but had 22 turnovers. The Mavericks turned those miscues into 31 points.
Cavaliers 99, Heat 89:: Nobody in the NBA bounces back like the Cavaliers. LeBron James recorded a triple double, Mo Williams scored 29 points and host Cleveland (49-13) quickly shook off any hangover from a disappointing loss at Boston by beating Dwyane Wade and Miami (33-29).
Hawks 87, Pistons 83: : Josh Smith scored 19 points, Al Horford added 18 and they each grabbed 12 rebounds to help host Atlanta (35-28) beat Detroit (31-30), ending the Pistons' four-game winning streak.
Bucks 125, Warriors 120:: Richard Jefferson scored a season-high 35 points and host Milwaukee (29-36) held off a big rally by Jamal Crawford and beat Golden State (21-41) to end a three-game losing streak.