On February 28th, the U.S. Department of State announced that Chile would be added to the Visa Waiver Program. Beginning May 1, 2014, nationals of Chile may enter the United States without a visa, provided they meet the requirements of the Visa Waiver Program. The full announcement is available here.
The Visa Waiver program allows nationals of countries with low rates of visa refusal to visit the United States for temporary periods of 90 days without applying for a visa at a U.S. Embassy or Consulate. Those seeking to use the Visa Waiver Program must meet program requirements and use the Electronic System for Travel Authorization (ESTA) to get pre-approval before coming to the United States.