Wall Street advanced on Thursday as progress toward ending the Iran war buoyed investor sentiment, while disappointing results from Broadcom led a chip selloff that held the Nasdaq's gains in check.The blue-chip Dow surged, hitting a record closing high with a boost from healthcare and financial stocks.The S&P 500 posted more muted gains, while the Nasdaq ended essentially unchanged. Chipmaker Broadcom missed revenue expectations, sending its shares tumbling and casting a pall over the AI frenzy, which has sent chip stocks soaring so far this year."About the only blemish on the market at this point is Broadcom, and I think investors are buying the dip," said Paul Nolte, senior wealth adviser and market strategist at Murphy & Sylvest in Elmhurst, Illinois. "I don't think investors have given up on chips yet, but what they've yet to come to grips with, 'Is this real? Are these valuations legitimate?' I'm not sure yet that investors hav...