English, the National Basketball Assn.'s seventh-leading scorer with a 25.3-point average, was held to two free throws by halftime and finished with 13 points before fouling out with 1:38 remaining.
Jay Vincent scored a career-high 42 points for the Nuggets, who dropped their third straight game.
Nance had 20 of his points by halftime along with 3 of the Suns' 9 blocked shots, which set a club record for a half.
Jay Humphries added 16 points for the Suns, while Walter Davis and Alvan Adams each had 14 and rookie Armon Gilliam 12.
Blair Rasmussen came off the bench to score 18 for the Nuggets, while Mike Evans had 15 points.
It was only the fifth victory for the Suns over the Nuggets in their last 17 meetings.