Preheat oven to 400F.
Heat the oil over medium in a large skillet and cook onion until softened.
Add in the garlic, cumin and coriander and cook for 30 seconds.
Add the chicken and cook until done.
Melt butter in a medium saucepan.
Whisk in the flour to make a roux, stir and cook until bubbly then whisk in chicken stock
Bring to a boil, whisking frequently.
Remove from heat and stir in sour cream and green chilies. Season with salt and pepper.
Add a little sauce to the bottom of the baking dish.
Add 1 Tbs cheese to each tortilla and divide cooked chicken evenly between tortillas.
Roll each on up and place seam-side down in the baking dish.
Pour sauce evenly over enchiladas.
Top with remaining cheese.
Bake at 400F for 20 minutes until cheese is melted and the sauce near edges of baking dish is bubbly.
Remove from oven and let cool for 5 minutes.
If using, sprinkle cilantro over the top.