1. Spray 5-quart slow cooker with cooking spray; add onion slices.
2. In 10-inch nonstick skillet, heat oil over high heat. Sprinkle taco seasoning mix over pork shoulder, pressing to coat. Brown pork in oil on all sides; remove from skillet to slow cooker. Pour enchilada sauce on top of pork.
3. Cover; cook on High heat setting 4 to 5 hours or until tender. Remove pork from slow cooker; shred meat with fork. Place shredded pork in large bowl. Add chiles, 2 cups of the sauce from slow cooker and the onions; stir well.
4. Spoon pork mixture onto tortillas. Add toppings. Roll up tortillas.
1. Any leftover carnitas filling is just as delicious the next day on tacos, in enchiladas, or even on pasta!
2. Play around with different topping to create your favorite carnita!