For the second time in two months, Kaiser Permanente nurses have walked off the job at the HMO’s Los Angeles headquarters to protest working conditions they say compromise patient safety. About 1,100 nurses are staging the one-day action Wednesday outside Kaiser’s Los Angeles Medical Center on Sunset Boulevard to protest staffing ratios they call inadequate. “We’re the people with the hands-on contact with patients, who actually know what they require,” said veteran nurse Lise Geller. “We want to deliver something much better than average care.” The nurses have been joined in the walkout by 1,400 other Kaiser employees, including social workers and psychologists from offices around Southern California. They complain about patients facing lengthy delays for their services.