Put the chicken in a 6-quart crockpot.
Add salt, pepper, onion powder, garlic powder, chili powder, and ground cumin.
Add the onions, drained chilies and enchilada sauce on top.
Cover and cook for 3 to 4 hours on high or 6 to 8 hours on low, until the chicken is cooked.
Shred the chicken with 2 forks.
Add the sour cream, green onion and cooked rice, along with half a cup of the cheese.
Sprinkle the remaining cheese on top and cook until the rice is heated through (15 to 45 minutes on high).
When the cheese starts to bubble, the casserole is ready to serve.