Preheat a waffle iron to its medium-high setting.
In a large mixing bowl, sift together the flour, baking powder, and salt.
In a separate container, whisk together 2 eggs, 1.5 cups milk, and melted butter until emulsified.
Combine the wet and dry ingredients, stirring until just incorporated, then fold in the shredded cheddar cheese.
Ladle batter into the waffle iron and cook until golden brown; remove and immediately drape over a rolling pin or thick handle to create a taco shell shape while cooling.
In a skillet over medium heat, cook the breakfast sausage until browned and fully cooked, breaking it into small crumbles.
Whisk the remaining 6 eggs with 0.25 cup milk and scramble in a non-stick pan until soft curds form.
Season eggs with salt and pepper to taste.
Assemble by placing a portion of scrambled eggs and sausage into each waffle shell.
Garnish with chopped chives and serve immediately.