(Recasts, adds Nornickel official's comments, updates prices) By Manolo Serapio Jr MANILA, April 19 (Reuters) - Nickel surged more than 9 percent on Thursday to its strongest level since late 2014 on fears U.S. sanctions on major Russian aluminium producer Rusal may be broadened and could hit key Russian nickel supplier Nornickel. It was the second straight session of sharp gains for nickel, adding to Wednesday's 7.5-percent spike, spurred by worries over tighter global supply for a