Nolasco (7-6) allowed two runs -- one earned -- on five hits, picking up his first win in three starts. The right-hander struck out four without walking a batter to earn his second win against Washington this season.
Felipe Lopez homered for the Nationals, who have lost six of their last seven outings.
Washington's starting pitcher, Tony Armas Jr. (6-5), was activated off the 15- day disabled list and suffered the loss. The right-hander, who was sidelined for nearly a month with a right forearm strain, lasted five innings and allowed four runs on five hits.