WI pre Columbian civilisations fought their battles in similar formations to Europeans? Would their weapons change, within the limits of their stone, wood, bronze technology, eg would they develop heavy shields and long spears/pikes/sarrisas? How would the Spanish go when confronted by several thousand men in a shield wall?
Given that the Aztecs fought to obtain captives to sacrifice rather than to kill, that is extremely unlikely in their case without changes to their culture which would make them virtually unrecognizable as Aztecs.
The Inca, however, might well have done it, had bronze not been such a recent discovery (only about 150-200 years before the arrival of the Spanish). Inca armies fought to kill, and for reasons of statecraft rather than for religious reasons, just like Europeans did. But their pre-bronze weapons...primarily stone maces...were not really suitable for close-order fighting, and they didn't really have time to properly learn to use their bronze armaments before they were conquered. Have bronze be discovered in the Andes in say, 1,000 AD instead of 1250-1300, and you might very well see something of the kind develop by 1432...
As to what effect it would have, that's hard to say. They developed a really nasty bronze halberd-like weapon that would have been quite effective if used in a mass phalanx-like formation, especially in stopping the charges of Spanish cavalry. That is provided, of course, that the extra security provided by being in such a formation allows the men within it to remain in formation despite their fear of the horses themselves. Or the Spanish guns.
Assuming they are able to remain in formation, the Spanish have a real problem. Contrary to popular belief, most Conquistadors did not wear metal armor, other than, perhaps, a helmet. Most would have worn leather jerkins, quilted armor, or other light-weight armor. Only the wealthiest Conquistadors had metal armor. So the bronze Inca halberd would be quite effective against them. And even the men in metal armor have vulnerable points, since there is no evidence that ANY Conquistador wore full plate armor.
In the end, the Inca still will fall. Disease will do most of the dirty work, and Spain will eventually send across a large enough army armed with guns and pike tercios to handle the Incan phalanxes. But they will survive quite a bit longer and the conquest will be a much more bloody process for the Spaniards.