Preheat oven to 375°F. Lightly spray a 9 × 13 inch pan with cooking spray. Spread 1 cup salsa verde on bottom of pan.
2 cups (16 oz. jar) salsa verde, divided
In small frying pan, sauté onions with small amount of olive oil until softened, about 5 minutes.
¼ medium yellow onion, chopped
In large bowl, mix shredded chicken with ⅔ cup salsa verde, 1 ½ cups cheese, scant ¼ cup cilantro, sautéed onions, and salt and pepper to taste.
3 cups shredded cooked chicken, 16 oz. grated Monterey Jack cheese, divided, ⅓ cup chopped fresh cilantro, divided, salt and pepper to taste
Wrap tortillas in two paper towels and microwave for 30 to 45 seconds so that they are soft and easier to work with.
8 flour tortillas, more if needed
Spoon about ¼ cup of the chicken mixture into a tortilla. Roll up tightly and place seam side down in the baking dish. Repeat until you are out of filling. Drizzle enchiladas with remaining salsa verde (about ⅓ cup) and sprinkle with remaining cheese.
Spray a large sheet of foil with cooking spray and use that to cover the baking dish. Bake for 25 minutes, remove foil and bake for five more minutes.
Sprinkle with remaining cilantro, let stand for a few minutes and serve, topped with sour cream, if desired.
Video
Notes
Shredded chicken: Make easy shredded chicken in your Instant Pot. Rotisserie chicken, canned chicken, or leftover chicken can be used, too.
Sauce variations: Substitute homemade salsa verde if you'd like. A can of red enchilada sauce can be substituted, or homemade enchilada sauce.
Vegetarian: Instead of chicken, fill the enchiladas with fajita-style vegetables (grilled peppers and onions), and a can of black beans, rinsed and drained.