Preheat the oven to 375°F and grease a 9 x 13-inch baking dish.
Heat the oil in a pan and then add the flour and cook for a minute.
Pour in the chicken broth slowly, whisking until the mixture is smooth.
Stir in the tomato paste, salt, cumin, chili powder, and oregano.
Bring the mixture to a boil, then reduce the heat and simmer for 10 minutes.
Stir the chicken with 1 cup of the shredded cheese and the onion.
Divide this mixture between the tortillas and roll them up.
Put them in the prepared back dish and pour the sauce on top.
Cover and bake for 15 minutes.
Uncover and add the rest of the cheese and bake for 5 minutes or until the cheese has melted.
Enjoy!