The 23-year-old native from Charlotte, North Carolina, rallied from a two-race slump to claim his first Cup victory in Miami following a late dominating run.
The 18-year-old grandson of NASCAR Hall of Famer and team owner Joe Gibbs will return for an additional 14 Xfinity Series races throughout the 2021 season.
The 23-year-old native from Mooresville, North Carolina, is slated to make his first Xfinity start of the season at Dover International Speedway in May.
The 26-year-old Ferguson from Lincolnton, North Carolina, will make his second career Truck start with Kaulig Racing more than a month after making his Truck debut at Bristol.
Spire Motorsports has earned one win and three top five finishes. Rajah Caruth took the checkered flag in last year's Rackley Roofing 200 after leading 61 laps.
In 12 previous NASCAR Cup Series starts at Nashville (Tenn.) Superspeedway, Spire Motorsports has two top-five finishes with a best result of second earned twice by Zane Smith (2024) and Carson Hocevar (2025).