NEW YORK—Jerome Powell may still be the clear favorite to get renominated as Federal Reserve Chairman, but some investors are considering the long-shot alternative should there be a surprise change. Powell’s odds in betting markets have fallen following sharp criticism of his performance by progressive Democrats and a trading scandal among Federal Reserve officials. Online betting website Predict Powell a 76 percent chance of being confirmed by the Senate, down from a 90 percent chance on Sept. 12 although up from a 61 percent chance in late September, while the odds that Federal Reserve Governor Lael Brainard will be nominated have increased to 18 percent from a low of 6 percent in September. Brainard, who was nominated to the Fed board by former President Barack Obama in 2014, is widely seen as more dovish than Powell in part because of her push to retain super-easy monetary policy until there is …