Preheat your oven to 350 degrees Fahrenheit.
Pour one tablespoon of olive oil in a large skillet and sauté onion and garlic in it over medium high heat for five minutes or until they are translucent (do not brown).
Add the chopped chicken breasts, shredded Cheddar cheese, four ounces of chopped green chillies, and ½ teaspoon of red chilli powder to the sautéed onion and garlic.
In the meanwhile put the enchilada sauce in a microwave safe flat dish and heat it in the microwave for 40 to 45 seconds. Remove the sauce from the microwave and dip the tortillas in it.
Lay the tortillas dipped in enchilada sauce on a work surface and spoon the chicken mixture into them.
Roll the tortillas to enclose the filling, tuck in their ends and place them in a baking dish with the seam-side facing down.
Pour one quarter cup olive oil in a saucepan and blend flour into it. Stir in the chicken broth and cook the mixture until it thickens.
Also stir in jack cheese, sour cream and the remaining enchilada sauce. Season your sauce with chilli powder to taste and pour it over the stuffed tortillas.
Bake the tortillas in the preheated oven for half an hour.
After half an hour remove the baking tray from the oven, sprinkle shredded cheddar cheese and bake again in the oven until the cheese melts.