Freshman forward Jeffrey Carroll, making his first career start, scored 15 points and grabbed 11 rebounds for the Cowboys (3-0).
Guard Darrian Dempsey scored 12 points and had three rebounds to lead Division II NW Oklahoma State (1-2).
For the first time this season, Oklahoma State started the game in peak form, blazing out to a 23-4 lead through the first eight minutes, holding NW Oklahoma State to just 1-for-12 shooting over that span.
It was clear that coach Travis Ford's message was received after he voiced his displeasure with their effort and intensity during their 74-52 win over Prairie View A&M Sunday afternoon.
Nash, who scored 15 points and had seven rebounds Sunday, totaled six points and grabbed five rebounds just in the first eight minutes.
NW Oklahoma State pushed back a little bit after that, scoring six straight points to pull to within 23-10, but the Cowboys reeled off another dominant run, of 17-3 over the next four minutes to put the game out of reach.
After two consecutive games with slow starts followed by strong second halves, Oklahoma State dominated right from the start and kept the pressure on the whole way. They led 49-20 at halftime and never let up, outscoring the Rangers 14-3 over the first seven-plus minutes of the second half to build an insurmountable 63-23 advantage.
Junior Jeff Newberry, a junior college transfer who played most of the second half, scored a career-high 14 points, 10 in the second half. He shot 5 of 6 from the field, including 3 for 3 from beyond the three-point line.
Oklahoma State senior Michael Cobbins sat out the fourth game (including one exhibition contest) to complete his NCAA-mandated suspension for playing in two games during his redshirt season of 2010-11.
Northwestern Oklahoma State scored on the game's first shot, as Adrian Motley sank a three-pointer from the top of the key, to take a 3-0 lead. OSU's Nash tied the game with a free thrown 30 seconds later and NW Oklahoma State never held the lead again.
Oklahoma State hosts Milwaukee on Friday.
Northwestern Oklahoma State returns home to host Cameron on Friday.