* Closing 68 earns Spaniard another victory * Overnight leader Ernst ties for second (Adds quotes, detail) Nov 13 (Reuters) - Four weeks after winning her maiden LPGA title in South Korea, Spaniard Carlota Ciganda added a second with a two-shot victory at the Lorena Ochoa Invitational in Mexico City on Sunday. One stroke off the pace heading into the final round at Club de Golf Mexico, Ciganda eagled the par-five second and birdied two of the next four holes on the way to a four-under-par 68 as she broke clear of a tightly bunched leaderboard. More...