Nicasio pitched six effective innings for his first victory in almost a year, and Wilin Rosario, Michael Cuddyer and Dexter Fowler homered to lift the Rockies over the Milwaukee Brewers 7-3 on Wednesday night.
The Rockies took two of three under Weiss, their new manager, in the season-opening series at Miller Park.
"Get good starting pitching and it tends to fall into place for you," Weiss said. "We were able to do something. If we can get starting pitching like that consistently, we're going to be in real good shape -- particularly with our offense."
Nicasio (1-0) did his part using his fastball.
He allowed two runs and seven hits for his first win since last April 30, when he beat the Los Angeles Dodgers. Winless in the next five starts, he suffered a season-ending knee injury on June 2.
"I threw my fastball inside, away, and nobody can hit my fastball," Nicasio said. "The hitter needs to show me he can hit my fastball inside. If he does, OK, I'm going to throw my breaking ball. But if nobody can hit it, I'm going to throw it."
Weiss said that Nicasio had it all working against the Brewers.
"He's firing strikes. He's got a great arm," Weiss said. "When he's in good counts, he's going to be tough to get to.
Weiss had a hunch coming out of spring training that his team could hit.
"I felt all spring that this is going to be a good offensive club," he said. "It's only three games, and you have to be careful, but we're a good offensive club and have a lot of good players."
Twelve of the Rockies' 19 runs scored in the three-game series came off eight home runs.
Rickie Weeks hit a solo home run and Alex Gonzalez added an RBI single off Nicasio. Ryan Braun drove in a run off Chris Volstad, but that was it. Rex Brother and Rafael Betancourt kept the Brewers scoreless the rest of the way.
Weiss liked what the four pitchers did in the game.
"And it was a big effort for us," he said. "Our bullpen was a bit short for us tonight. Juan was big. Volstad was huge. Brothers was huge. Great team win."
Rosario picked up right where 2012 ended for him when he hit a two-run homer in the second. The young catcher led all NL rookies with 28 home runs and 71 RBIs last season, which were also franchise rookie records.
Rosario's nice defensive play saved Nicasio from further trouble in the third.
Weeks hit his first home run of the season. Braun singled, took third on Aramis Ramirez's double and scored on Alex Gonzalez's line-drive single. Ramirez rounded third as left fielder Carlos Gonzalez charged the ball, picked it cleanly and fired a strike to Rosario, who took the offline throw, dived at Ramirez as he slid home and tagged him.
The last two seasons have been tough on Nicasio. On Aug. 5, 2011, he was hit in the head by a line drive and needed season-ending surgery to repair vertebrae in his neck. In 2012, he made his first appearance on the opening day roster and was 2/3 with a 5.28 ERA before getting hurt.
"This is a great win for him," Weiss said. "I'm proud of him. All the stuff he's been through, this has to be a great feeling for him."
Peralta, who made the opening-day roster after a decent spring, went 5 1/3 innings, allowed six hits, walked three and struck out four.
"He's got great stuff, but he's got to learn to get it over the plate," Brewers manager Ron Roenicke said.
Roenicke said that the team was battling, but it just wasn't enough.
"We scratch out some runs, then turn around and give them up in a hurry," he said. "That's hard to keep up the pressure on the other guys when they keep coming back and scoring runs."
Volstad took over for Nicasio and allowed a two-out double to Weeks, who scored on Braun's double in the seventh.
Cuddyer came on as a pinch-hitter in the seventh and stayed in the game in right.
In the sixth, center fielder Carlos Gomez robbed Gonzalez of homering in his third straight game. Gomez tracked the ball to the outfield padding and then jumped, snagging the ball well above the top of the wall.
LHP Jeff Francis starts against San Diego in the Rockies' home opener Friday. Colorado's last home-opener win came April 9, 2009, against the Padres. ... RHP Kyle Lohse makes his Milwaukee debut when the Brewers face the Diamondbacks on Friday. He went 1-0 with a 0.77 ERA against Arizona last season. ... Weiss gave Todd Helton and Cuddyer the day off and started Eric Young Jr. in right and Jordan Pacheco at first. Weiss said the move was simply to get them some playing time. ... The Rockies will work out Thursday afternoon at Coors Field. The public gets in free with the donation of canned food item. Otherwise, it's $1.