Cherokee International Inc., a Tustin manufacturer of power-supply products, has opened a subsidiary in Guadalajara, Mexico, to make and sell its products to Mexican firms. The 26,000-square-foot plant, which opened in August and now employs 75 workers, already is operating at capacity and will be expanded to a 55,000-square-foot facility to accommodate 300 workers within a year, according to Cherokee marketing director Lonnie L. Friend. Most employees are being hired from the Guadalajara area, though the new president, Nereo Agostinelli, was previously director of eastern regional sales in Florida. The operation will not affect the 350 employees at the company’s Tustin plant, Friend said. Cherokee also has small plants in Tecate, Mexico, and Bombay, India.