Nash will race under the Tickford Autosport banner this year, putting him on the path towards Supercars.
The teenager will drive for Paul Morris and his Nemo Racing team in the seven-round TransAm Series.
His second season in the five-round Toyota GR86 Cup will be with Ash Seward Motorsport.
Nash enjoyed his first taste of a TransAm car at Queensland Raceway in recent days.
“I know it’s going to be another step up in my racing career, but we all believe this is the right move,” said Nash.
“It’s going to be a very jam-packed season with 11 rounds in total, but I believe in myself, and I’ll be putting 110 percent into both categories.”
Nash’s step up to the TransAm Series marks the first opportunity for him to get behind the wheel of a V8-powered car.
“Racing in TransAm will help me understand how a car reacts to different driver inputs and mechanical changes,” said Nash.
“Learning this at a young age will be crucial for my progression later in my motorsport career.
“The test went amazing! Sitting on the left-hand side and using a dog straight-cut gearbox was a weird feeling at first, but by the end of the day, I felt at home in the car.
“Working with the Norwell team was fantastic, and we kept improving my time and knowledge about the car.”
The return of Mark Winterbottom to the Tickford Racing fold alongside Thomas Randle and Cameron Waters will have its benefits for the Tickford Autosport juniors.
“Thomas and I have worked closely together over the last couple of years, and I owe a lot of my knowledge to him – not just in driving but in media as well,” said Nash.
“Now, I’m excited to work with Frosty. He has over 20 years of experience in the Supercars paddock, and I’ve looked up to him ever since I was a kid in the FPR days.”