Blue Chips Flat After Wal-Mart News  NEW YORK (Reuters) - U.S. blue chips were little changed on  Monday as a disappointing sales forecast from Wal-Mart Stores  Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=WMT.N target=/stocks/quickinfo/fullquote"&gt;WMT.N&lt;/A&gt;, the world's biggest retailer, offset the effect  of easing oil prices.