Combine chicken, ⅔ cup sour cream, taco seasoning, and 1 cup of cheese in a bowl.
Soften cream cheese in a large skillet over medium heat. Stir in enchilada sauce, remaining ⅔ cup sour cream, and jalapenos. Spread ½ cup of the sauce in the bottom of a 2-quart baking pan.
Divide the chicken mixture over the tortillas. Roll and place seam-side down in the prepared pan. Repeat with remaining tortillas. Pour sauce overtop.
Cover and bake for 15 minutes. Uncover, top with remaining cheese, and bake 5-10 minutes more or until cheese is melted and bubbly.
Notes
Tightly cover and refrigerate leftovers for up to 4 days.
You can freeze for 1-3 months, but the sauce will be grainy and watery when it thaws, so it's better not to.