In a large bowl, whisk together eggs, melted butter and buttermilk. Add in pancake mix, cornmeal, chili powder and salt. Blend until smooth.
Heat waffle iron and spray with non-stick spray. Scoop batter onto hot waffle iron and cook 2-3 minutes or until done. Repeat with remaining batter.
In a large bowl, mix together all ingredients together for spicy mayo. Drizzle over cooked waffles and garnish with cotija.