tires on his final pit stop. Chastain won the 2019 Circle K Firecracker 250 at Daytona driving the No. 16 Camaro for Kaulig Racing. Chastain's teammates Justin Haley and A. J. Allmendinger finished behind him, though Allmendinger was subsequently disqualified for failing post-race inspection. Chastain would later win at Pocono Raceway in the Truck Series in commanding fashion, dedicating his win to Kaulig crew chief Nick Harrison, who had died the previous week. In Xfinity Series competition at Watkins Glen International, Chastain sent Justin Allgaier spinning off the track in the bus stop portion of the circuit; Allgaier, thinking the move was intentional, wrecked Chastain in the same section of the track later in the race, relegating Chastain to a 34th-place finish. Chastain chalked his side of the incidents up to mistakes while Allgaier cited instances of Daytona earlier in 2018 and Las Vegas in 2018 as further dirty racing by Chastain. Once Chastain's berth in the Truck Series playoffs was secure, CarShield announced full sponsorship of his playoff efforts. Chastain would earn his second top-five of 2019 when he finished second to Christopher Bell at Texas Motor Speedway in November, leading 29 laps. 2020 On October 15, 2019, it was announced that Chastain would be driving for Kaulig Racing full-time in the 2020 NASCAR Xfinity Series. Chastain also returned to the Cup Series at the Daytona 500 and Coca-Cola 600, driving the No. 77 in a partnership between Chip Ganassi Racing and Spire Motorsports. He also retained his ride with Niece Motorsports in the Truck Series in a part-time capacity, moving over to the organization's No. 44 entry and sharing the ride with Carson Hocevar and Natalie Decker. Chastain failed to qualify for the Xfinity season opener at Daytona after mechanical issues plagued his car. However, Kaulig and RSS Racing forged an agreement that RSS driver Jeff Green surrender his No. 38 car to Chastain for the race. In the Daytona 500, Chastain was involved in a late wreck with Ryan Preece that took him out of the race. On February 19, 2020, Roush Fenway Racing announced Chastain would replace an injured Ryan Newman in the team's No. 6 Ford starting with the Pennzoil 400 at Las Vegas. Chastain drove the No. 6 for three races before the season was put on hold due to the COVID-19 pandemic. Newman returned to the No. 6 when the season resumed while