But CAS fined the Ecuadorian Football Federation (FEF) 100,000 Swiss francs for submitting a document with “false information”, the court said on Tuesday.
Ecuador will also be docked three points at the start of the 2026 World Cup qualifying campaign, it added.
The Chilean federation had alleged that full-back Byron Castillo played for Ecuador despite being Colombian, a claim dismissed by world football governing body FIFA in a September ruling, reports Xinhua.
CAS said it acknowledged testimony from Ecuadorian authorities that Castillo was an Ecuadorian national.
“While the player’s Ecuadorean passport was indeed authentic, some information provided therein was false,” CAS said.
“In particular, the panel was comfortably satisfied that the player’s date and place of birth were incorrect since the player was actually born in Tumaco, Colombia, on 25 June 1995. The panel deemed it necessary to hold the FEF liable for an act of falsification… even if the FEF was not the author of the falsified document but only the user.”
Ecuador have denied any wrongdoing and FEF officials said they were analysing the possibility of appealing the fine and points deduction.
The South American side will begin their World Cup campaign in the tournament opener against hosts Qatar on November 20 before meeting Senegal and the Netherlands in their other Group A matches.