Stir 3/4 cup picante sauce, sour cream and chili powder in a medium bowl.
Stir the picante sauce, chicken and cheese in a large bowl,.
Spoon about 1/3 cup chicken mixture down the center of each tortilla. Roll up the tortillas and place seam-side up in a lightly greased 11x8-inch shallow baking dish. Pour the remaining picante sauce over the filled tortillas. Cover the baking dish.
Bake at 350F for 40 minutes or until the enchiladas are hot and bubbling. Top with the onion.