Goran Dragic had 13 points and six assists for the Suns, who won two of their last three.
The Suns capitalized on poor Denver shooting to extend a five-point halftime lead to 62-51 on an 18-foot jumper by Beasley with 5:07 left in the third quarter.
The Nuggets were 4 of 22 from the floor in the period and scored just 11 points. Phoenix only was slightly better at 7 for 24, but the difference was enough for the Suns to carry a 67-57 lead into the fourth.
Phoenix led by as many as 18 in the final quarter.
Beasley finished 13 of 21 from the floor, including 3 for 3 from beyond the arc, and added 10 rebounds. The rest of the Suns shot 34.8 percent (23 of 66).
Denver, which lost its fourth straight, had 31 field goals and 26 turnovers.
Beasley scored eight straight points in the second quarter as the Suns rallied from a 37-34 deficit to take a 41-39 lead with 4:39 left in the first half. Beasley added a running 5-footer and Dragic hit a pair of free throws to put Phoenix ahead 51-46 at halftime.
Brian Windhorst explains that Wednesday's joint statement from the Miami Heat and Chris Bosh, saying that Bosh won't return this postseason, puts both sides on the same page for the first time in a while.
Ian Begley updates the latest on the Knicks' coaching search with Kurt Rambis and David Blatt appearing to be the most attractive options right now, but Phil Jackson would have to reconsider if Frank Vogel is no longer the Pacers coach.
Chris Forsberg breaks down how Danny Ainge and the Celtics have positioned themselves through the last few seasons by being patient and acquiring draft picks to potentially become an attractive suitor for high-value free agents.