The former world number one had been expected to make his long-awaited comeback at the Brazil Open on February 11, although he will now return a week earlier than originally planned.
The Spaniard has been out of action since his shock second-round defeat to Lukas Rosol at Wimbledon in June while a possible comeback last month was curtailed by a stomach virus.
The 11-time grand slam winner's illness ruled him out of the Australian Open, which began in Melbourne on Monday.
Nadal has not contested an ATP tournament in South America since 2005 and is naturally delighted to be returning to the Andean country.
"I am delighted to confirm my participation in the tournament in Vina del Mar in Chile," he wrote on Twitter.
"I would like to thank the tournament organisers for the invitation and say I have many fans in the Andean country, I can finally go in person to be with them and play my first tournament after the injury that has kept me so long section.
"Thank you very much and see you at Vina."