Preheat the oven to 375 degrees F, ensuring a rack is in the center position. Wrap the tortillas in damp paper towel and microwave for 30 seconds – 1 minute, until warm and pliable. Set aside for enchiladas assembly.
In a large bowl, combine the chicken, half of the cheese (2 cups), and all of the green onions, jalapeno, and spices (chili powder – dried oregano). Season with 1 teaspoon kosher salt and ground black pepper to taste. Toss to combine well.
Lightly coat a rimmed quarter sheet pan with nonstick spray, then layer the enchiladas as follows:
Layer 2: Spread the chicken mixture over the tortillas. Spread ⅓ of the enchilada sauce over top.
Layer 3: Top with the remaining tortillas, using a spatula to tuck in any loose sides along the edges. Spread the remaining enchilada sauce over top, then sprinkle the remaining cheese.
Spritz a large piece of aluminum foil with nonstick spray and cover the pan loosely. Bake for 30 minutes, until heated through. Remove the foil and bake uncovered for 5-10 minutes longer, until the cheese is melty and golden.
Slice the sheet pan enchiladas into 6-8 pieces. Serve immediately with finely chopped fresh cilantro and a drizzle of Mexican crema or sour cream. Enjoy!
