In January 2017, Nash was added to Munster's squad for the 2016–17 European Rugby Champions Cup. On 3 February 2017, Nash made his competitive debut for Munster when he started against Edinburgh in a 2016–17 Pro12 fixture. He scored his first try for Munster on 26 November 2017, coming off the bench against Zebre in round 9 of the 2017–18 Pro14 and helping the province to a 36–19 away victory. He signed a one-year development contract with Munster in January 2018, which saw him join the senior squad for the 2018–19 season. Nash was nominated for the 2018 John McCarthy Award for Academy Player of the Year in April 2018.