Prepare sauce: Blend salsa verde, avocado and chilies in adobo sauce in small bowl.
Portion onto center of each warm tortilla in a rectangle 2/3 cup scrambled eggs, 2 ounces chicken, 1/3 cup tomatoes and 1 tablespoon green chilies. Sprinkle on 1 ounce cheese.
Roll up tortilla, envelope-style, by folding bottom half of tortilla up over the filling, tucking the edge around the filling, and then folding the two sides in, and rolling the tortilla up to fully enclose the filling.
Serve with salsa and garnish with cilantro, if desired.
Roast tomatillos, serrano and onions under broiler 5-6 minutes per side until softened with some black spots, flip once. Remove tomatillo skin and cut out cores. Roast garlic in a dry skillet for 15 minutes until softened and darkened. Cool and remove skins.
Throw all in a blender or food processor with juices and puree. Add lime juice and cilantro and season. Chill. If it gets too thick in fridge, just add water to desired consistency. This will pick up heat as it sits, so adjust amount of serrano pepper down if you intend to make a batch for a couple of days of service.
In a large bowl, beat the eggs with a fork until well blended, then add the grated butter, mixing until well combined. The butter will emulsify into the eggs and keep them fluffy and tender, even when cooked through.
Heat a nonstick skillet over medium low heat. Spray with nonstick spray. Pour the egg and butter mixture into the pan. Using a heat-proof rubber spatula to scramble the egg mixture until firm throughout with no visible egg liquid remaining, and large curds have formed. Season to taste with salt and pepper.
Note: Do not let uncooked egg mixture remain at room temperature for longer than one hour (including preparation and service time).