Nuno made just one mistake, but it was enough to sink him as the Rockies beat the D-backs, 2-0, at Chase Field.
With one out in the second inning, Nuno hung a breaking ball to Matt McBride, who deposited it over the wall in left for the lone run Nuno allowed as he retired the final 20 batters he faced.
"I don't know what more you can do," D-backs manager Kirk Gibson said. "He gave up a home run and retired 20 in a row, didn't walk anybody, struck out seven guys. It's a shame. He did his job."
Nuno is still looking for his first win in a D-backs uniform. In 10 starts for Arizona, the lefty has a 3.23 ERA, and he has not allowed more than two runs in his last four starts.
Yet he still is without a win.
"He's been good the whole time he's been here," Gibson said. "We have not scored for him."
Tyler Matzek (4-9) held the D-backs in check, allowing just three hits in seven innings of work.
"He's been on a roll and he's got a good arm, a good live arm, moves the ball around, has a good slider, went to his changeup later and kept us off balance," Gibson said. "He just mixed up his pitches. We knew what he was doing, we just didn't put good at-bats on him. He's got some good deception, obviously. Matzek threw a good game, but you'd hope you could score when you have a guy like Nuno throwing a game like that."
The Rockies went to their bullpen to start the eighth, and the D-backs had their best scoring chance in that inning.
Ender Inciarte singled with one out off Christian Friedrich, and Cliff Pennington reached on a Friedrich error to put runners at first and second.
Friedrich, though, got David Peralta to strike out, and then right-hander Adam Ottavino came on to get Mark Trumbo to tap weakly to third to end the inning.
"One of the things we need to work on is our quality of at-bats with guys in scoring position and our two-strike approach," Gibson said. "We've been on a bad run right now. Probably part of it is that we've got a lot that we're giving the guys, trying to get them to understand certain things so they can progress. Sometimes it works against you."
The Rockies added an insurance run in the ninth when Charlie Blackmon hit a solo homer off reliever Matt Stites.