Nelson Mariano is a Filipino chess grandmaster. He was born on September 28, 1974 in Bacoor, Cavite, Philippines. Mariano began his career in competitive chess during his middle school years and distinguished himself in various tournaments during his teen years. In 1992, he won the Under-20 World Junior Chess Championship in Buenos Aires, Argentina, and as a result was awarded the International Master (IM) title by the International Chess Federation (FIDE). It was the first time a player from the Philippines had won the prestigious championship.
In 1995, Mariano became a grandmaster, the highest title in international chess, by winning a tournament in Pardubice, Czech Republic. He was the third Filipino to earn this title.
Apart from being a competitive player, Mariano also served as a professional chess coach and chess columnist. He was the chess coach of the Far Eastern University in Manila, Philippines. He also wrote a chess column in the Philippine Star.