What did the OC billionaire do when the wife was away? Computer-chip magnate Henry T. Nicholas III won big in a 1998 public stock offering for his Broadcom Corp., and to celebrate, he built an extravagant $30 million underground “personal brothel” at his Laguna Hills estate. That's according to the latest allegations discovered by E. Scott Reckard and Kim Christensen, two Los Angeles Times reporters who dug up court documents containing the dirt. Last week, newspapers disclosed FBI interes