On 5 November 2005, Nash fielded for Australia as a substitute in a
Test match against the
West Indies, for whom he would later play. He dropped a catch fielding at point. On 12 August 2008 Nash was named in the
West Indies One Day International (ODI) squad to play in the tri-series against
Bermuda and
Canada. In the second match of the series, against Canada, Nash scored 39 not out batting at number six, sharing in an unbeaten 111 run partnership with
Xavier Marshall who in that innings broke the record for most sixes in an ODI innings. He finished with figures of 10–1–56–3. In the final that followed, also against Canada, Nash took 1/33 and did not bat as the West Indies won by seven wickets. On 1 November 2008, the ODI squad to tour Pakistan was announced, with Nash as one of the members.
John Dyson, the West Indies coach, stated that Nash's performance against Canada and Bermuda had shown he was ready to perform against leading cricket teams such as Pakistan. Nash made his Test debut for the West Indies on 11 December 2008, playing against
New Zealand. In the same match, fast-bowler
Lionel Baker also made his debut. It was widely reported in the media that he was the first white man to play for the West Indies since
Geoff Greenidge played five Tests in the early 1970s. He was subjected to racial abuse for being a "white boy" during trials for Jamaica.
Chris Gayle, Jamaica's captain, helped Nash telling him that "You are one of us, don't worry about what anyone's saying to you. If anyone troubles you, I am here for you." It later emerged that he was of mixed race. During the fifth Test in Trinidad Nash scored his maiden Test century, his innings of 109 included 17 fours. He shared a 234-run fifth wicket partnership with Chanderpaul. Nash continued his good form in the first Test against England with 81 during a 143-run partnership with
Denesh Ramdin who made 61. In November 2009, less than a year after making his Test debut, Nash was awarded a central retainer contract with the West Indies Cricket Board (WICB). Nash was appointed West Indies vice-captain in October 2010. The previous captain and vice, Chris Gayle and
Dwayne Bravo, had chosen not to sign central contracts with the WICB and were replaced. In the final fixture of the three-match series, Nash passed 1,000 Test runs. The series was a 0–0 draw with bad weather curtailing the matches. Nash scored 160 runs at an average of 53.33. Nash was the third-highest run-scorer for the 2010/11 season of the Caribbean regional first-class tournament, scoring 626 runs from nine matches at an average of 62.60; Jamaica won the tournament. In the semi-final of the competition, Nash scored his maiden first-class double century, scoring 207 runs off 349 balls and beating his previous highest score of 176. Pakistan toured the West Indies in
April and May 2011, and Nash was selected for the two-Test series. The series was drawn 1–1, with West Indies securing their first Test victory in nearly two years. Nash scored 44 runs in four innings. Between 13 October 2007 and 27 May 2011, Nash scored 1,093 Test runs for West Indies at an average of 35.25, with only Shivnarine Chanderpaul, Chris Gayle, and Ramnaresh Sarwan scoring more for the team. India
toured in June and following a run of poor form – scoring 53 runs in his last six innings – was dropped after the first Test. In October, Nash's central contract with the WICB was allowed to lapse. ==Post-retirement life==