Preheat the oven to 400°F (200°C). Spray a 9x13-inch baking dish with nonstick spray and set aside.
Heat a large skillet over medium-high heat, add the olive oil and minced garlic, and sauté for about 2 minutes until fragrant.
Season the thinly sliced skirt steak with salt and pepper, add to the hot skillet, and cook about 3 minutes per side until medium doneness. Remove the steak and set aside to rest, then slice if needed.
Drain excess oil from the skillet, return it to medium heat, and melt the butter.
Add the whisked eggs and the green chiles to the skillet and scramble with a spatula until soft curds form; season with salt and pepper and remove from heat.
Place the stand-and-stuff taco shells in the prepared baking dish. Put one slice of pepper jack cheese into the bottom of each shell, folding the slice so it comes up the sides to help prevent sogginess.
Divide the scrambled eggs among the shells, then top each with 2–3 slices of cooked steak. Sprinkle shredded cheddar over the tacos.
Bake in the preheated oven for 12–14 minutes, or until the cheese is melted and the shells are toasted.
Remove from the oven and garnish with pico de gallo, chopped cilantro, and sour cream. Serve warm.