Nash left after sustaining nerve damage near his left knee, apparently in a collision, with five minutes left in the third quarter Sunday at Staples Center. He had eight points and two assists in 21 minutes as the Lakers' two-game winning streak came to an abrupt end.
Nash was playing in only his third game since returning from almost three months of inaction because of nerve damage in his back.
He played well last Friday against Philadelphia, accruing 19 points and five assists the same day he turned 40.
Center Chris Kaman had 27 points and 10 rebounds for the Lakers, who fell to 18-33 after never leading Sunday's game. It was Kaman's best game with the Lakers. He made 13 of 23 shots and had two blocked shots.
Lakers reserve point guard Kendall Marshall had 13 points and 11 assists, jumping back into a prominent role after Nash's departure.
Center Joakim Noah had 18 points and 13 rebounds for Chicago (25-25), which finished 3-3 on a six-game road trip.
Bulls 52, Lakers 46 (halftime)
Both teams dressed only nine players because of injuries, and the Lakers trailed at halftime, 52-46, Sunday at Staples Center.
Taj Gibson has 16 points for the Bulls. Gibson played college basketball a few miles away at USC.
The Bulls dopped down to nine players after announcing before the game that Carlos Boozer would sit because of a calf injury.