Stir together the chicken verde and chopped spinach until well blended.
In a large pot combine the sour cream, milk, green chilis, monterrey jack cheese, and garlic powder. Cook on the stovetop at medium heat until melted and combined.
Spoon a small amount onto the bottom of a large glass baking dish and spread it to cover the bottom of the dish.
Fill each tortilla with a heaping 1/2 cup of the chicken mixture. Roll the tortilla and place seam side down next to each other tightly in the baking dish.
Cover the enchiladas with the remaining sauce and then top with the mexican blend cheese mixture.
Bake at 350?F 30-40 minutes or until heated through and the cheese on top is melted and the sauce is bubbly.