Shred the chicken as well as the cheeses and set aside.
Prepare the enchilada sauce in a medium to large mixing bowl by whisking together the oil, arrowroot powder (if using), chili powder, tomato paste, water, cumin, garlic powder and onion powder. Set aside.
When all is prepared, put half off the chicken in each half of the spaghetti squash.
Ladle on plenty of enchilada sauce, as much as you like. (you might have a little left over. It makes a lot, but it freezes well!)
Cover each half of the squash with half the cheese and place the squash halves on a parchment-lined baking sheet.
Bake at 375 F. for 20 minutes, or until the cheese is fully melted.
Using two forks, scrap the spaghetti squash up inside the skins, mixing everything together as you go. Feel free to add a little more sauce if it seems too dry.
Serve with a salad or other veggie on the side. (I made roasted asparagus, but most veggies will work here.)
Please note that the data below is a ballpark figure. Exact nutrition data is not possible.