Preheat your oven to 375°F (190°C).
In a skillet, heat olive oil over medium heat. Add diced onions and sauté until translucent, about 3-4 minutes.
Combine shredded chicken, cumin, half the green enchilada sauce, and half the cheese in a mixing bowl. Stir until evenly combined.
Warm the corn tortillas in a dry skillet for about 30 seconds per side to make them pliable.
Fill each tortilla with the chicken mixture and roll them up, placing seams down in a greased baking dish.
Pour the remaining green enchilada sauce over the top and sprinkle the remaining cheese evenly.
Bake in the preheated oven for 20-25 minutes, until cheese is melted and lightly golden.
Remove from oven, garnish with sour cream, and serve immediately.