The 25-year-old, who joined the Spanish outfit on loan from Atletico Rafaela, had previously been linked with a number of European clubs.
"I am conscious of arriving at a very important team and it's a dream come true to come and play in Europe," he told reporters at a press conference.
"The team has had a very good campaign and has qualified for the Europa League and that was one of the motivations for coming. I hope to give back all the confidence that Betis has put on me."
Betis finished seventh in La Liga last season.