Lightly spray a large baking dish, about 9”x13” with a cooking spray. Spread half of the bread across the bottom of the dish, followed by half of the roasted chicken.
Sprinkle half of the shredded cheese along with half of the scallions over the chicken.
Spoon 1 cup of the salsa and about half of the black beans over the top.
Repeat the layers finishing with the black beans.
Whisk together the eggs and the half and half with the green chilies, the kosher salt and black pepper.
Ladle the egg custard over the bread and chicken mixture. Cover the dish tightly with a plastic wrap and refrigerate overnight.
About 30 to 45 minutes before baking pull the casserole from the refrigerator to take the chill off. If the baking dish is still cold to the touch place it on a rimmed baking sheet before popping it into the oven.
Bake the strata uncovered in a 375-degree oven for 50 to 55 minutes or until it’s golden around the edges and puffed and set up in the middle.
Allow the strata to rest for about 10 minutes to finish setting up before serving.
Top with a dollop of sour cream, a slice or two of fresh avocados and tomatoes.