The Nuggets closed within a half game of Dallas for sixth place in the Western Conference and Phoenix fell into the 10th spot, a half game behind Utah.
The Suns took a 99-96 lead on a layup by Steve Nash with 3:16 to play and did not manage another point. Phoenix missed its last nine field goal attempts.
Afflalo hit five 3-pointers and made 11-of-19 overall. Al Harrington came off the bench to add 23 points for the Nuggets.
Shannon Brown scored 18 for Phoenix. The Suns turned the ball over 16 times to only five for Denver.