MEXICO CITY, March 1 (Reuters) - Tesla will open a gigafactory in Mexico, Chief Executive Elon Musk said on Wednesday, as the electric vehicle behemoth pushes to expand its global output. Mexico on Tuesday said Tesla had chosen the northern border state of Nuevo Leon for a new factory worth more than $5 billion, calling it the "the biggest electric vehicle plant in the world". See here for a complete list of exchanges and delays