CHICAGO (Reuters) - A dozen years after his death and more than three decades after he left the White House in disgrace, Richard Nixon is alive as never before in the grand opera world, which can't seem to get enough of the him. "Nixon in China," the John Adams' opera first staged in 1987, is in the midst of a new wave of popularity and performances, the latest being a triumphal turn on the stage of the Chicago Opera Theater where it opened May 19. Adams' seductive yet complex and minimalist melodies, as well as librettist Alice Goodman's poetry turn...