The Cubs second loss in 12 games snaps a three-game winning streak.
Ryan Zimmerman also homered for the Nationals, who had lost seven of eight. Young added a double and finished 3-for-4, picking up his first hits since he was selected to the National League All-Star team on Sunday.
Chico, who was 0-and-1 in his previous eight starts despite giving up only 13 runs in those seven no-decisions, improves to 4-and-5.
Saul Rivera worked the eighth and Ray King completed the five-hitter for Washington's third shutout this season. The Cubs were blanked for the fourth time.
Cubs starter Rich Hill gave up all six runs over his six innings of work and falls to 5-and-6.