Rice. Beans. Tortillas, wheat flour and corn. CARBS, carbs, and more carbs.
Prior to arrival of Europeans, Meso-Americans survived mainly on corn and beans, mostly corn. The wealthy no doubt had more animal protein in their diets.
Outside Meso-America it’s likely wild game provided a balanced diet, even for tribes that were largely agricultural.
Of course, these observations are based on what the first Europeans to explore an area found. Most of the Americas was greatly depopulated, 75% to 90% or more, during the 1500s by waves of disease rolling out from the areas of contact with Europeans. Most of the Indians killed by the depopulation never saw a European.