Eric Cooper Jr.'s 3 off an assist from Coleman with 2:37 to play gave the Wolfpack the lead for good at 70-67. Isaiah Pineiro made 1 of 2 free throws to cut the lead to two.
Nevada's D.J. Fenner - off another assist from Coleman - hit a jumper to move the lead to 72-68. Cameron Forte made a layup to make it 72-70, but Coleman's 3 with 32 seconds left sealed the game.
Nevada (4-1) got 16 points from AJ West with eight rebounds and Fenner finished with 12 points and five rebounds.
Portland State (2-2) was led by Forte's 23 points and nine rebounds. Pineiro and Calaen Robinson each had 13 points. Pineiro had a double-double with 11 boards.