Chacin (5-3) posted a second win in two starts, yielding six hits without a walk while striking out three.
Rex Brothers got the game's final out for his third save as the Rockies took the rubber match of a three-game home series.
Carlos Gonzalez went 2-for-4 with a two-run homer and Wilin Rosario added solo shot to help stoke Colorado's offense.
Phillies starter Cole Hamels (2-10) absorbed the loss after giving up three runs on six hits in seven frames.
Ryan Howard went 2-for-4 with an RBI for Philadelphia.