Preheat the oven to 375°F (190°C).
Over medium heat in a skillet heat the vegetable oil. Add the diced onions and garlic, sautéing until they become translucent.
Add the shredded chicken to the skillet and mix it with the onions and garlic. Season with salt and pepper to taste, and cook for a few minutes until the chicken is heated through.
In a separate bowl, combine the sour cream and salsa verde, creating the creamy enchilada sauce.
In the baking dish, spread a thin layer of sour cream sauce on the bottom.
Take each corn tortilla and spoon some of the chicken mixture onto it. Roll up the item and position it with the seam facing down in the baking dish. Repeat with the remaining tortillas.
Pour the remaining sour cream sauce over the rolled tortillas, covering them entirely.
Sprinkle the shredded cheese over the top.
Cover the baking dish with aluminum foil and bake in the preheated oven for about 20 minutes or until the cheese is melted and bubbly.
Remove the foil and bake for an additional 5 minutes or until the cheese turns golden brown.
Garnish with fresh cilantro, if desired.
Serve the sour cream chicken enchiladas hot and enjoy!