Frito-Lay plans to open a potato chip plant in Visalia next year, increasing the city's work force by as many as 150 people. The Texas-based subsidiary of PepsiCo Inc. said it will begin manufacturing Lay's and Ruffles potato chips in a plant where Eagle brand snacks used to be made. Anheuser-Busch closed the plant a year ago. Frito-Lay will renovate the plant at a cost estimated as high as $60 million. City enticements included the waiver of $300,000 in sewer hookup fees.