Sanchez has struggled to fulfil his potential at Manchester United in recent seasons but looks back to his best for the national team as they hunt a third consecutive Copa America trophy.
Chile finished second in Group C behind Uruguay, losing 1-0 to La Celeste after securing victories over Japan and Ecuador in their earlier fixtures.
Sanchez was on target in both of those wins and held his nerve to slot home the winning penalty in the quarter-final shootout against Colombia.
Next up are Peru, who made it to the last four by beating Uruguay on penalties but were hammered 5-0 by hosts Brazil in the group stage and were held to a goalless draw against Venezuela.
Chile are favourites to make it through to the final, but Reinaldo Ruenda’s side must be wary of complacency against a supposedly inferior opponent.
La Roja have fielded a settled side throughout the tournament but have failed to score in their last two outings after falling foul of VAR reviews.
Despite this, Eduardo Vargas will continue to lead the line after two goals in four matches.
The Tigres striker will be supported by Sanchez and veteran Jose Pedro Fuenzalida, who also got on the scoresheet against Ecuador.
Erick Pulgar is expected to anchor the midfield alongside the combative duo of Arturo Vidal and Charles Aranguiz.
Defenders Mauricio Isla, Gary Medel and Jean Beausejour are all vastly experienced with the trio boasting over 100 international caps each.
The back four is likely to be completed by Guillermo Maripan while Gabriel Arias should line up between the posts.
Chile have won 12 of the last 14 meetings between the two sides, including the 2015 Copa America final.
Chile predicted line-up vs Peru – Copa America semi-final
(4-3-3): Arias; Isla, Medel, Maripan, Beausejour; Pulgar, Aranguiz, Vidal; Fuenzalida, Sanchez, Vargas