Nicasio (3-1) gave up just three hits and a walk while striking out two, and Corey Dickerson was 3-for-4 with an RBI and two runs scored for the Rockies, who have won four of five.
Carlos Gonzalez hit a home run in the win, but left in the fourth inning with a left index finger contusion. The team said he is day-to-day.
Bartolo Colon (2-4) was tagged for all seven runs on nine hits in just 4 2/3 innings for the Mets, who had won five of six coming into the contest.
Travis d'Arnaud hit a three-run home run and Juan Lagares drove in the other run in the loss.