In a two-lap dash to the finish, Nemechek got a big push from Daniel Hemric to take the lead.
Justin Haley, who controlled the restart and had a teammate in Chandler Smith right behind him, lost his pusher as Smith stumbled with low fuel.
Then, Haley battled his last remaining Kaulig teammate in Hemric for second place, which allowed the Joe Gibbs Racing driver to get away without further challenge.
For Nemechek, it was the fifth win of his career and his third of the 2023 season.
"I got a huge push from the No. 11 there, so thanks to Daniel (Hemric) for giving me that huge push," said Nemechek post-race. "Hats off to all of this No. 20 team. Early on in the race, if you would have said that we were going to win the race, I definitely would have told you that that wasn't going to be the case.
"We didn't have the fastest car tonight ... But I'm really proud of this whole No. 20 team. First win for Mobil 1 with me at JGR. Won with them in the Truck Series. Man, this is special ... Thank you to all the fans that came out tonight. I appreciate you guys."
Hemric finished second, Cole Custer third, Haley fourth, and Sam Mayer fifth. Ty Gibbs, Kyle Sieg, Parker Kligerman, Josh Williams, and Sammy Smith rounded out the top-ten.
Stage 1
C. Smith led the field to the green flag at the start of the race, but Josh Berry mounted an immediate challenge to the inside. He eventually cleared him, and took control of the race lead.
Behind them, there was a sketchy moment between Cup regulars Gibbs and Haley as they negotiated for room down the backstretch.
The pack began to stretch out and it became single-file with Smith trying to retake the lead, but to no avail. Instead, he was shuffled back to fifth in the running order.
A couple laps later, Kligerman spun with a flat left-rear tire. While most of the field took the opportunity to pit, several frontrunners chose to stay out as they hoped to capture as many stage points as possible.
The six-lap dash to the end the stage culminated with a daring outside pass by Riley Herbst to steal the stage win away from Berry.
C. Smith, Haley, Austin Hill, Justin Allgaier, Jeremy Clements, Sheldon Creed, Joe Graf Jr., and Parker Retzlaff rounded out the top-ten.
Stage 2
The drivers who decided to pit before the stage end inherited some track position with Creed now leading Mayer.
Stage 1 winner Herbst restarted back in 15th. Jeb Burton, struggling after a no-tire call, was nearly the cause of an incident as he got put four-wide. Fortunately, all drivers escaped unscathed.
The caution flag then flew as Ryan Sieg and Creed battled for the lead when Retzlaff slid down the track.
Later on in the stage, 2023 ARCA Daytona winner Greg van Alst crashed heavily, ending his Xfinity debut in a shower of sparks and flames. Mason Massey was also collected in the wreck.
The race resumed with nine laps to go in the stage. Gibbs had to get on the brakes after Berry slammed the door on him, causing the JGR driver to shoot up the track. Kyle Weatherman made slight contact with him and even hit the outside wall, but all those involved managed to carry on.
Hill then pushed his teammate Creed into the lead, and the RCR duo proceeded to go back-and-forth for the lead.
Creed prevailed in the end, winning the stage over Hill, R. Sieg, Berry, Allgaier, Custer, Hemric, C. Smith, Kligerman, and S. Smith.
Stage 3
Hill lost eight spots choosing to take four fresh tires during the pit stops that followed. Stage 2 winner Creed lost even more after a slow stop due a fueling issue. He then returned to pit road for a second stop.
Gibbs hit the wall and cut a tire on the restart, but before he could limp it back to pit road, chaos erupted in the pack in front of him.
Herbst slowed with a flat tire as well, igniting a multi-car crash that eliminated several contenders from the race. R. Sieg, Creed, Jones, Alfredo, Weatherman, and Mayer were among those who suffered significant damage in the incident.
Herbst, Sieg, Jones, Alfredo and Creed were all unable to continue.
Big crash out of turn two.
— NASCAR on NBC (@NASCARonNBC) July 9, 2023
📺: @USANetwork pic.twitter.com/DHJmcykdeZ
Kaulig Racing was now in firm control of the race, running 1-2-3 as the green-flag waved once again. Behind them, Berry was the latest driver to find the wall and fall off the pace.
The seventh caution of the race flew as Weatherman’s difficult day finally came to an end, slamming the wall with a flat tire and grinding to a halt at pit entry.
Hill, who had won the last two NXS races at Atlanta, began to charge forward. He picked off the frontrunners one at a time, but after splitting the Kaulig trio, he made a move for the lead that did not work out. He fell from second to sixth with 35 laps remaining.
While desperately trying to break the Kaulig blockade late in the race, Hill spun and pushed the race into overtime.
It was on that final restart when Nemechek managed to snatch the lead away from Haley and hung on as the Kaulig teammates battled amongst themselves.
He led only three laps, crossing the finish line just over two tenths clear of Hemric.
| Cla | # | Driver | Manufacturer | Laps | Time | Gap | Interval | Laps Led | |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 20 |  John Hunter Nemechek |
Toyota | 169 | 2:24'32.923 | 3 | |||
| 2 | 11 | Daniel Hemric |
Chevrolet | 169 | 2:24'33.168 | 0.245 | 0.245 | ||
| 3 | 00 | Cole Custer |
Ford | 169 | 2:24'33.349 | 0.426 | 0.181 | ||
| 4 | 10 | Justin Haley |
Chevrolet | 169 | 2:24'33.379 | 0.456 | 0.030 | 80 | |
| 5 | 1 | Sam Mayer | Chevrolet | 169 | 2:24'33.490 | 0.567 | 0.111 | ||
| 6 | 19 | Ty Gibbs | Toyota | 169 | 2:24'33.555 | 0.632 | 0.065 | ||
| 7 | 28 | Kyle Sieg | Ford | 169 | 2:24'33.613 | 0.690 | 0.058 | ||
| 8 | 48 | Parker Kligerman |
Chevrolet | 169 | 2:24'33.656 | 0.733 | 0.043 | ||
| 9 | 92 | Josh Williams |
Chevrolet | 169 | 2:24'33.731 | 0.808 | 0.075 | ||
| 10 | 18 | Sammy Smith | Toyota | 169 | 2:24'33.906 | 0.983 | 0.175 | ||
| 11 | 25 | Brett Moffitt |
Ford | 169 | 2:24'34.505 | 1.582 | 0.599 | ||
| 12 | 21 | Austin Hill |
Chevrolet | 169 | 2:24'34.544 | 1.621 | 0.039 | 1 | |
| 13 | 27 | Jeb Burton |
Chevrolet | 169 | 2:24'35.252 | 2.329 | 0.708 | ||
| 14 | 26 | Kaz Grala |
Toyota | 169 | 2:24'35.262 | 2.339 | 0.010 | ||
| 15 | 51 | Jeremy Clements |
Chevrolet | 169 | 2:24'35.342 | 2.419 | 0.080 | ||
| 16 | 31 | Parker Retzlaff | Chevrolet | 169 | 2:24'36.653 | 3.730 | 1.311 | ||
| 17 | 7 | Justin Allgaier |
Chevrolet | 169 | 2:24'38.736 | 5.813 | 2.083 | ||
| 18 | 91 | Josh Bilicki |
Chevrolet | 168 | 2:24'36.217 | 1 Lap | 1 Lap | ||
| 19 | 8 | Josh Berry | Chevrolet | 168 | 2:24'38.926 | 1 Lap | 2.709 | 34 | |
| 20 | 16 | Chandler Smith | Chevrolet | 168 | 2:25'06.561 | 1 Lap | 27.635 | 5 | |
| 21 | 38 | Joe Jr. | Ford | 167 | 2:24'36.441 | 2 Laps | 1 Lap | 4 | |
| 22 | 35 | David Starr |
Toyota | 167 | 2:24'37.418 | 2 Laps | 0.977 | ||
| 23 | 45 | Jeffrey Earnhardt |
Chevrolet | 167 | 2:24'37.597 | 2 Laps | 0.179 | ||
| 24 | 08 | Mason Massey | Ford | 167 | 2:24'40.339 | 2 Laps | 2.742 | ||
| 25 | 43 | Ryan Ellis |
Chevrolet | 167 | 2:24'40.604 | 2 Laps | 0.265 | ||
| 26 | 4 | Garrett Smithley |
Chevrolet | 167 | 2:24'43.878 | 2 Laps | 3.274 | ||
| 27 | 24 | Parker Chase |
Toyota | 167 | 2:24'56.144 | 2 Laps | 12.266 | ||
| 28 | 6 | Brennan Poole |
Chevrolet | 165 | 2:24'38.672 | 4 Laps | 2 Laps | ||
| 29 | 53 | Akinori Ogata | Chevrolet | 103 | 1:55'30.728 | 66 Laps | 62 Laps | ||
| 30 | 07 | Mason Maggio | Chevrolet | 102 | 1:50'30.810 | 67 Laps | 1 Lap | ||
| 31 | 36 | Kyle Weatherman |
Chevrolet | 97 | 1:33'56.167 | 72 Laps | 5 Laps | ||
| 32 | 02 | Blaine Perkins | Chevrolet | 96 | 1:32'14.698 | 73 Laps | 1 Lap | ||
| 33 | 9 | Brandon Jones |
Chevrolet | 91 | 1:27'17.215 | 78 Laps | 5 Laps | ||
| 34 | 78 | Anthony Alfredo | Chevrolet | 90 | 1:27'52.463 | 79 Laps | 1 Lap | ||
| 35 | 2 | Sheldon Creed |
Chevrolet | 88 | 1:19'40.483 | 81 Laps | 2 Laps | 24 | |
| 36 | 98 | Riley Herbst |
Ford | 88 | 1:25'20.189 | 81 Laps | 5'39.706 | 3 | |
| 37 | 39 | Ryan Sieg |
Ford | 87 | 1:18'32.217 | 82 Laps | 1 Lap | 15 | |
| 38 | 44 | Greg Van | Chevrolet | 62 | 49'43.447 | 107 Laps | 25 Laps |
