Sánchez has 27 caps for Argentina, since his debut at 21 May 2010, in a win over Uruguay, in Santiago, Chile. He has 2 tries, 25 conversions, 44 penalties and 5 drop goals scored, 207 points in aggregate. He participated at the 2011 Rugby World Cup where he played in one match, without scoring. He has been playing at The Rugby Championship, since the admission of the Pumas in 2012, counting currently 16 games, with 10 conversions and 28 penalties scored, 104 points in aggregate, in four presences at the competition.
Sanchez was picked for the Argentina 2015 Rugby World Cup squad. He was the top point scorer in the competition with 97 points and he had the second highest number of penalties scored, finishing with 20. His display of talent in the tournament helped his to team to achieve a fourth-place position.