Prep & Brown the Sausage: Preheat your oven to 375°F (190°C). Lightly grease a standard 9x13-inch ceramic casserole baking dish with cooking spray or butter. Heat a large skillet over medium-high heat. Add the turkey breakfast sausage, breaking it apart with a wooden spoon, until browned and cooked through (about 6-8 minutes). Transfer the sausage to a paper towel-lined plate to drain; wipe excess grease from the pan.

Soft Scramble the Eggs: In the same skillet over medium-low heat, melt 1 tablespoon of butter. In a medium mixing bowl, vigorously whisk together the eggs, whole milk, kosher salt, black pepper, and garlic powder until pale and frothy. Pour into the warm skillet and gently fold with a silicone spatula into soft, creamy curds. Remove from the heat while still slightly glossy (they will finish baking in the oven). Gently fold in the cooked sausage and drained green chilies.

Sauce the Dish & Roll Tortillas: Spread 1/2 cup of red enchilada sauce across the bottom of the prepared 9x13 baking dish. Warm the corn tortillas in the microwave between two damp paper towels for 30 to 45 seconds to make them soft and pliable without cracking. Spoon about 1/3 cup of the warm egg-and-sausage filling down the center of each tortilla, sprinkle with a pinch of cheddar cheese, tightly roll up, and nestle seam-side down in the dish in a single snug layer.

Smother with Sauce & Cheese: Pour the remaining 1.5 cups of red enchilada sauce evenly over the tops of the rolled enchiladas, ensuring every exposed tortilla surface is coated to lock in moisture. Scatter the remaining shredded cheddar, Monterey Jack cheese, and sliced green onions evenly over the top.

Bake to Molten Perfection: Bake uncovered at 375°F (190°C) for 25 to 30 minutes, or until the cheese is completely melted, bubbling along the edges, and lightly golden brown in spots. Remove from the oven and let rest on a trivet for 8 to 10 minutes so the savory layers set cleanly.

Garnish & Serve Warm: Top the casserole with dollops of cool sour cream, diced avocado, freshly diced Roma tomatoes, and chopped cilantro. Cut into 8 hearty squares and serve immediately with warm salsa or your favorite hot sauce!