By Caroline Valetkevitch NEW YORK (Reuters) – Major U.S. stock indexes closed mostly lower on Monday, led by a more than 2% drop in Nasdaq, as investors sold tech and big growth names ahead of this week’s Federal Reserve meeting and an expected hike in interest rates. The Dow ended flat, with financial and healthcare shares giving the index some support. Developments in the Ukraine-Russia conflict added to investor caution as Russian and Ukrainian delegations held a fourth round of talks on Monday, but no progress was announced, while Russian forces allowed a first convoy of cars to escape Ukr…