Gonzalez tripled and hit a two-run homer for the Rockies, winners in five of their last six games. Todd Helton also homered, while Chacin (7-9) withstood four hits and four walks and struck out seven to pick up the victory.
"He's really beginning to arrive," Rockies manager Jim Tracy said of Chacin. "He is definitely a huge bright spot for our club with what's taken place this season."
"I had a good fastball, but my off-speed wasn't there," Billingsley said. "You have days like that."
Both National League West teams are stuck in the middle of the wild card race, as the Rockies stayed within 4 1/2 games of the Phillies and Los Angeles fell 5 1/2 games behind the pace-setters.
Casey Blake, who hit a grand slam to carry LA in the opener of this three-game set, doubled home James Loney in the second inning for an early lead, then was walked intentionally to load the bases in the fourth.
Chacin was able to get Jamey Carroll to ground out and end the threat, and the Rockies went ahead in the bottom half.
Gonzalez tripled leading off and came in on a single by Troy Tulowitzki, who moved to second on a walk to Helton and scored two batters later on Melvin Mora's base hit up the middle.
Helton made it 3-1 with a leadoff blast in the sixth, the second straight game he went deep. Billingsley had not allowed a homer in 92 innings coming into the at-bat, which was the longest active homerless streak in the majors.
Ronald Belisario relieved the LA starter in the seventh and hit pinch-hitter Ryan Spilborghs to start the inning. Two outs later, Gonzalez launched a no- doubter over the wall in right-center for his 27th home run of the year. Belisario then plunked Tulowitzki and was promptly ejected.
Dodgers outfielder Manny Ramirez, who was apparently claimed by the Chicago White Sox off waivers earlier this week, was out of the starting lineup for the third straight game as the teams attempt to work out a deal for the slugger. He did, however, pinch-hit in the seventh inning and struck out..Helton hit home runs in consecutive games for the first time since August 30-September 1, 2009...LA still leads the season series, 7-4.