Preheat the oven to 350°F. Lightly coat a 9×13-inch baking dish with nonstick cooking spray and set aside.
Heat a medium skillet over medium heat. Add the chorizo and cook for about 5 minutes, breaking it into crumbles as it cooks, until browned and cooked through. Remove from the heat and set aside.
In a large mixing bowl, combine the cilantro, green chiles, jalapeño, eggs, melted butter, milk, heavy cream, salt, black pepper, cumin, chipotle powder, chili powder, and Mexican oregano. Whisk until thoroughly combined.
Slice 8 of the croissants in half horizontally, as you would for a sandwich. Set the top halves aside. Tear the remaining croissants, along with the bottom halves of the sliced croissants, into medium-sized pieces.
Arrange half of the torn croissant pieces evenly in the bottom of the prepared baking dish. Reserve ½ cup of the cheese for topping. Sprinkle half of the cooked chorizo and about half of the remaining cheese over the croissants. Pour enough of the egg mixture over the layer to moisten the croissants.
Repeat with the remaining torn croissants, chorizo, and cheese, reserving a small amount of the egg mixture for the top.
Arrange the reserved croissant tops over the casserole. Gently press them down so they absorb some of the egg mixture, then pour the remaining mixture evenly over the top.
Bake for 20–25 minutes, or until the casserole is golden, bubbly, and the egg mixture is set.
Remove the casserole from the oven and sprinkle the reserved ½ cup of cheese in between and around the croissant tops. Return to the oven and bake for about 5 minutes more, or until the cheese is melted.
Let the casserole rest for 5–10 minutes before serving. Enjoy warm!