I myself had my own very possible timeline where "Asians" discover America and colonize/meddle in Meso-Andes-American affairs.
https://www.alternatehistory.com/discussion/showthread.php?t=79289
Map. But I have made many different threads for my Timeline 420:Ming-Mexica-Inca, so just go to my profile and look to all the threads I have started. Specially Timeline 420 and Follow the Setting Sun.
Basicly where the Ming Explorations do not halt (Though the Treasure Fleets are reduced in size).
So by 1512 we have a Ming Empire that has made the Indian Ocean and the Pacific as well into their personal lakes (Australia being once again a prision for any European sailors that venture into Ming waters) and have made limited settlement along the California coast and are investing in a canal in Meso-America.
Where the Ming have made protectorates of the Mexica (Aztecs) and Inca, giving them better everything (though weapons and ships are very, very regulated) and helping save a much larger portion of the native populations (Though folks north and west of OTL Texas are not so lucky) from disease or properly quaratining major outbreaks.
From this the Mexica and Inca have expanded beyond their borders (Inca is only contained by it's preferance for Mountain regions and the Mexica tot he North, the Mexica likewise contained by the Inca to the south and a Ming-Protected Pueblo-Apache Confederation and Commanche tribes to the North) OTL and quite the match for any Spanish expeditions.
So far I have up to 1521, but have not messed with this Timeline for sometime, I am stuck somewhere with either a Papal Crusade and/or the Mexica taking the fight to push the Spanish out of the Carribbean (Though I have figured this out that the Mexica due to the Ming imposed ship ban-use hired Chinese merchantmen to transport their invading armies across the Carribbean).