It's cool by the Colombian who now calls the Dallas area home and has at least shared the lead after all three rounds.
Munoz shot a 6-under 66 at TPC Craig Ranch on Saturday and was 21 under, a stroke ahead of hometown favorite Jordan Spieth, who shot a 64.
Spieth, who has three majors as part of his 13 career wins, is still seeking his first victory in the Nelson, where he contended in the final round as a 16-year-old high schooler in 2010 and has never finished higher than ninth.
"So having a chance to win this event, this will be kind of the best chance I've maybe ever had going into Sunday," Spieth said. "Done a good job not putting too much pressure on myself. I just wanted to get into contention and obviously see what needs to be sharpened for next week.
"But there's no better prep for a major than winning the week before."
The PGA Championship is next week at Southern Hills in Tulsa, Oklahoma.
Joaquin Niemann will be the third player in Sunday's final group. He's alone in third another shot back after a 65.
Munoz, who played in college nearby at North Texas, is 2½ years removed from his lone PGA Tour win.
"Besides winning in Bogota, Colombia, I've never been the favorite of any other place," Munoz said. "So it's a familiar spot. Jordan is, of course, the golden boy here, so everyone's favorite. I'm good friends with him, so it's going to be a lot of fun tomorrow."
Munoz made a 39-foot birdie putt on the par-4 second hole and holed a long bunker shot on the short par-4 sixth.
A West Texas native and Dallas-area resident seeking his first individual victory since 2010, Ryan Palmer shot a 70 and was 17 under with defending champion K.H. Lee (67) and 2011 Masters winner Charl Schwartzel (68).
Masters champion Scottie Scheffler, who overcame a triple bogey early in the second round for an outside shot to make a Sunday run, recorded birdies in bunches in a 65 -- including four of the last five holes -- that left him at 16 under.
"I haven't really seen the ball go in very much, which is frustrating because you got to make putts out here to shoot low scores," said Scheffler, another Dallas resident. "I fought my way kind of back into the tournament, but I need a hot putter tomorrow if I want to make some noise."