What if the Tupac Amaru Rebellion beats the Spanish in South America? They had conquered most of modern day Peru along with large chunks of Bolivia, Chile, and Argentina before their leader was killed and it just kinda blehed out.
Although Tupac Amaru was an indigenous movement never sought independence from Spain .. actually, in all documents, demonstrating their loyalty to the King of Spain. The rebellion was against local authorities.
For an Indian was inconceivable (unthinkable) rise against El Rey or like they called him "el Tataita".
If they did gain their independence would the Spanish or indeed anyone else manage to conquer it a second time round?