The Americans don't get hit with the plague apocalypse

[Arkenfolm]

That being said, you cannot expect them to be extremely effective with said guns. They may be, but it is not a given. After all, the introduction of weapons to Africa mainly allowed African kingdoms to capture more slaves to sell to European and or Islamic buyers.

But they were highly effective with guns, and their biggest obstacle was a supply of guns, tools for repairing guns, and powder for the guns. All of which Europeans would be much more eagerly helping them TTL. And I'm describing North Americans OTL. More organised states like the Inca or Mesoamericans (who might recruit European mercenary commanders to assist them) can master European firearms and modern tactics as well as anyone can--of course, tactics change in the New World based on geography. And as I suggested, a Native American slave trade would emerge and be sustained more than OTL's Native American slave trade. I think the experience of Africa is relevant to TTL's New World to some degree or another.

 

[Balaur]

No reason to be antagonistic........ However, look to how the Timurids prepared for the superior Ottoman firearms and their use of Serbian 'black armored knights'. Or, the heavily armored cavalry the Abbasid period adopted to combat the Byzantine Cataphracts, Abbasid-Umayyad naval tactics to counteract the superiority of Greek naval arms, etc....

Mind you, the Ottoman army that engaged the Timurids was thousands of disciplined warriors, easily the greatest army of the time (except the massive hordes of cavalry filed by Timur) and some of the most heavily armored horsemen of the period. Yet, Timur prepared for this and avoided the Serbian knights with his army and outmaneuvered the Ottoman infantry which would later, with the same doctrine obliterated the greatest general of the period, in Is'mail al-Safviyyah.

Those were within the context that their leaders expected to deal with, and they had years of planning and experimentation.
Not so with Pizarro's cavalry. To his credit, Atahualpa anticipated the threat and tried to deal with it, by having soldiers who panicked at the sight of horses killed, and by having a huge number of bodyguards accompany him. He very clearly knew an ambush was a possibility and took steps to deal with the threat, but it wasn't enough against the tactical and technological advantages the Spanish had.

 

[Balaur]

Well being ambushed and deceived is not a military strength either. Part of how old world armies operated was by deciet, which in the New, they did not have clear conceptions of.

From John Hemmings Conquest of the Incas:
"The Indians had never before seen the Christians retreat, and thought they were doing it as a trick to lure them onto the plain"
That sounds like a clear conception of military deceit to me. Certainly more of a conception of it than the Anglo-Saxons at Hastings had...

 

[John7755 يوحنا]

From John Hemmings Conquest of the Incas:
"The Indians had never before seen the Christians retreat, and thought they were doing it as a trick to lure them onto the plain"
That sounds like a clear conception of military deceit to me. Certainly more of a conception of it than the Anglo-Saxons at Hastings had...

Military deception is different than what the Spanish practiced. Military deceit has been practiced likely since the stone age and the Aztec knowledge of it speaks to a Stone Age civilization's ability to know such things. But how will the Aztecs understand kitman? Spain and its conquest of the New World is not too different to the Umayyad conquest of the Mid East and it makes sense the way in which Spain went through it, considering a large portion of their military ideals had developed from the Almohads.

 

[Avrorrange]

The Battle of Otumba stands against your view.

That is oversimplified. The Spanish defeated the highly numerous Inca forces in their first engagement. As well, the Inca regardless of civil war had a vast numerical superiority. They also had greatly alienated indigenous tribes of the area.

With enough numbers,even professional armies can be defeated by poorly armed mobs.

 

[John7755 يوحنا]

With enough numbers,even professional armies can be defeated by poorly armed mobs.

Can be, but not always and typically peasant revolts fail. As well, the Spanish are fighting well trained troops, just ones completely outclassed by them.

 

[Avrorrange]

Can be, but not always and typically peasant revolts fail. As well, the Spanish are fighting well trained troops, just ones completely outclassed by them.

Except they are heavily outnumbered,in unfamiliar territory and months from Spain.Many of them are just greedy bastards who can most likely be persuaded to switch sides if things go south.Peasant rebellions typically fail because they generally never evolve beyond the level of an armed mob and were generally poorly led.In this case,they will be led by their nobles.