Indeed the conquest of the americas didn't include that many battles anyway. The enormous success of the conquest was mainly based on the European diseases that the American population were not resistant to, causing them to be decimated in a few years.
Precisely. And what few 'battles' there were were almost allways lopsided affairs with handfuls of spanish conquistadors running roughshod over loads of lightly armed and armored Indian troops.

The technology and brutality disparity were almost impossible to overcome.

Sure sure, individual native tribes had undoubtedly brutal aspects of their society (human sacrifice anyone?) but their warfare was just not on the same level as the Europeans...it wasn't anything even approaching the coldly methodical European approach to 'total war'.