Stir 3/4 cup picante sauce, sour cream and chili powder in a medium bowl.
Stir the picante sauce mixture, chicken and cheese in a large bowl.
Spoon about1/3 cup chicken mixture down the center of each tortilla. Roll up the tortillas and place seam-side up in a lightly greased 11 x 8-inch shallow baking dish. Pour the remaining picante sauce over the filled tortillas. Cover the baking dish.
Bake at 350 degrees F for 40 minutes or until the enchiladas are hot and bubbling. Top with the onion.