Nash's late-game heroics enabled the Suns to rebound from a 10-point loss to Oklahoma City Saturday.
Phoenix used 16 points and nine rebounds from Markieff Morris and 15 points from Jared Dudley to post the victory.
Monta Ellis put in 18 points and dished off 11 assists for Golden State, which saw its two-game winning streak snapped.
Brandon Rush contributed 13 points for the Warriors.
Notable deaths of 2014 [PHOTOS]
UPI Sports Results for September 19, 2014