With Mario Chalmers and Ray Allen missing and Chris Bosh and Dwyane Wade struggling, James came up big for the Heat, shooting 13 of 18 from the field and having seven assists in his eighth 20-point game this season.
Kemba Walker had 22 points to lead the Bobcats, who shot 35 percent from the field.
Los Angeles' Blake Griffin had 30 points and 12 rebounds as the Clippers beat Brooklyn 110-103.
J.J. Redick added 26 points for the Clippers, who have not lost to the Nets since 2010.
Andray Blatche and Mason Plumlee scored 19 points each for Brooklyn, which was missing four of its five regular starters.
Houston's Dwight Howard scored 18 of his 25 points in the fourth quarter, including 13 of 19 free throws in a 2-minute stretch, to lead the Rockets to a 122-11 win over Denver.
Chandler Parsons added 20 points for the Rockets, who never trailed and led by as many as 23.
The Nuggets tried to get back in it with about 5 minutes left by fouling Howard every time Houston had the ball. The plan backfired and Howard, who entered the game shooting 49 percent from the line, finished 17 of 24 on free throws.
Ty Lawson had 28 points and a career-high 17 assists to lead Denver.
Dallas' Monta Ellis had 19 points and eight assists to help the Mavericks beat the Magic 108-100 and win at Orlando for the eighth straight time.
Dirk Nowitzki and DeJuan Blair added 18 apiece for the Mavericks.
Arron Afflalo led the Magic with 25 points and four assists.
Golden State's Klay Thompson scored 25 points as the Warriors held off Utah 102-88 for their third-straight win.
Andre Iguodala had 16 points and six rebounds for Golden State, which went ahead by 19 points late in the second quarter.
Derrick Favors finished with 17 points and seven rebounds for the Jazz, who fell to an NBA-worst 1-10.
Atlanta's Jeff Teague scored 16 points to lead eight players in double figures for the Hawks, who won 110-90 to send New York to a fifth straight home loss.
Cleveland's Kyrie Irving scored nine of his 41 points in overtime to help the Cavaliers beat Washington 103-96 and snap a three-game skid.
Minnesota's Kevin Love had 23 points and 12 rebounds and Nikola Pekovic had 20 points and 12 boards to lead the Timberwolves past Boston 106-88.
New Orleans' Anthony Davis had 13 points, nine rebounds and a career-high eight blocks in less than three quarters, helping the Pelicans rout Philadelphia 135-98 and emphatically snap a three-game skid.
Oklahoma City's Russell Westbrook scored 26 points and Kevin Durant added 24 as the Thunder beat Milwaukee 92-79.