Make the enchilada sauce according to the recipe instructions. You can use it as soon as it’s ready, or make it ahead of time and store it in the refrigerator for at least a week before using it.
Preheat your oven to 375°F. Grease a 9-inch x 13-inch baking dish, and set it aside.
In a medium-size mixing bowl, mix the shredded chicken with about 1/2 cup of the enchilada sauce and the 1/2 cup sour cream.
Cover the bottom of the baking dish with about 3/4-cup of the enchilada sauce.
Warm the tortillas of choice until they're soft and pliable. You can heat them in a hot-dry cast skillet, but I generally warm them in the microwave. Wet 2 paper towels and don’t wring them out completely. Place one on a microwave-safe plate, place the tortillas on top, and place the second paper towel on top. Microwave on high for about 30 seconds.
Working with one warm tortilla at a time (keeping the others covered with the paper towels so they don’t dry out), spoon about 3 tablespoons of the filling across the bottom half of a softened tortilla. Top with about 2 tablespoons of shredded cheese.
Close the tortilla by rolling it away from yourself until closed. Place the filled tortilla into the prepared baking pan, seam side down.
Repeat with the remaining tortillas, placing them side by side in the baking dish. Pack them in tight, so they don't open.
Pour about 3 cups of the remaining enchilada sauce on top of all the enchiladas.
Sprinkle the top of the dish with another 3 to 4 ounces of shredded cheese.
Place the dish in the oven and bake for about 20 minutes, or until the cheese is melted, and the sauce is bubbling.
Serve immediately, while hot.
Notes
How to cook the shredded chicken.Place 1 pound of raw skinless boneless chicken breasts in a lined or greased casserole dish. Drizzle them lightly with olive oil, sprinkle lightly with salt and freshly ground black pepper, and cover completely with parchment paper placed directly on top of it, covering the chicken completely.Preheat your oven to 400°F. Place the dish in the hot oven and cook for about 25 minutes or until an instant-read thermometer inserted into the thickest portion of each breast reads at least 165°F. Allow to rest outside the oven, still covered, for about 10 minutes before dicing or shredded to serve.