Easy, have Montezuma challenge Cortez's Conquistadors and the 2000 Talaxan troops in the open field before he gets to Tenoticlan (sic). The Spanish don't get control of Mexico by coup de main, and therefore don't get the idea that they can take Peru by coup de main. They begin a process of trade, missionary work and small wars to upset the local balance in Spains favour. This is still occuring when Drake arrives on the scene and throws a spanner inb the Spanish works, and there you have it a competition between Spain, declining local empires and England.