China is so vast, that during the campaign Timur would've died anyways, but I believe that Ming China would have been able to hold off Timur, but not the Northern Yuan Dynasty (Who would have helped Timur in a conquest of China). There is no way China could have fought a two-front war. China may have had the people, but early in the Ming Dynasty China wasn't in the economical situation to fight a war with Timur and the Northern Yuan Dynasty. China may have had the people to fight the war, but with the lack of equipment and lack of food (Timur would've cut off food and supplies) China would've lost a war.