The turnover soured an otherwise productive night for Nowitzki, who had 29 points and nine rebounds.
Chris Paul had 20 points and 11 assists for New Orleans (9-1), which avenged its only loss of the season Monday night in Dallas.
Jason Terry had 16 points in a reserve role and Jason Kidd had 11 points for Dallas.
HEAT 123, SUNS 96
In Miami, Chris Bosh scored a season-high 35 points, LeBron James finished with 20 points and Miami beat Phoenix.
Dwyane Wade added 17 points for the Heat, who blew it open with an 18-3 run to close the third quarter. James also had nine assists and eight rebounds.
Bosh had 22 of his points by halftime, already topping his previous Miami best of 21. All five Phoenix starters scored in double figures, led by Steve Nash's 17. Nash only had two assists, matching his lowest total since Dec. 29, 2008, against Oklahoma City, a span of 141 games.
Former Augusta State standout Garret Siler scored two points for the Suns in just over four minutes.
LAKERS 103, PISTONS 90
In Auburn Hills, Mich., Kobe Bryant scored 33 points without playing in the fourth quarter, and Los Angeles took advantage of Richard Hamilton's early ejection in a win over Detroit.
Pau Gasol added 25 points and 12 rebounds for Los Angeles.
Rodney Stuckey scored 18 points for Detroit.
CELTICS 114, WIZARDS 83
In Boston, Paul Pierce scored 23 points, and Rajon Rondo had 12 points and 13 assists before the Boston starters sat out the fourth quarter and watched the bench pull away.
Kevin Garnett scored 18 in 24 minutes, and Ray Allen had 11 points in 26.
Nick Young scored 20 points for the Wizards, who were without No. 1 overall draft pick John Wall and center Yi Jianlian for the second consecutive game.
RAPTORS 94, 76ERS 86
In Philadelphia, Andrea Bargnani scored a season-high 30 points, Sonny Weems added a career-high 25 and Toronto beat Philadelphia in a matchup of two of the worst teams in the Eastern Conference.
Elton Brand led the Sixers with 27 points.
TIMBERWOLVES 113, CLIPPERS 111
In Minneapolis, Michael Beasley scored 33 points and hit the winning jumper with 2.3 seconds to play to lift Minnesota.
Kevin Love added 24 points and 14 rebounds for the Timberwolves.
Eric Gordon scored 30 points and Blake Griffin had 26 points and 17 rebounds for the Clippers (1-11), who haven't won since beating Oklahoma City on Nov. 3.
THUNDER 116, ROCKETS 99
In Oklahoma City, Kevin Durant scored 24 points in three quarters, Russell Westbrook had 21 points and 12 assists and Oklahoma City beat Houston.
Luis Scola had 26 points and Kevin Martin scored 19 for the Rockets.