Preheat your broiler. Place half the onion, tomatillos, and jalapeno on a baking sheet and broil until the veggies are soft and a little brown, about 10 minutes. Make sure they do not burn and flip them if needed. Thinly slice the other half of the onion and save for later. Take the cooked veggies from the tray and add them to a blender with the sugar, 1/2 teaspoon of salt, stock, and blend to make your salsa.

Spray a 13 x 9 dish with cooking spray. Mix together the chicken, half of the shredded cheese, half of the cilantro, and 1/4 cup of the salsa. Wrap the tortillas in a damp paper towel and microwave for 1 minute. Working quickly take a tortilla and place some of the chicken mixture down the middle of the tortilla, wrap up and set in the baking dish seam side down. Repeat this until they are all in the baking dish.

Spray the tops of the enchiladas with some cooking spray and place under the broiler for a few minutes until they begin to turn golden. Remove from the broiler and top evenly with the remaining salsa and jack cheese. Again, place under the boiler until the cheese is melted and starting to brown. Remove and top with the sliced onion, crumbled queso fresco, and remaining cilantro. Enjoy!