Place breasts in glass baking dish. Slice onion thin and top chicken. Sprinkle with garlic powder and cumin.
Roast chicken covered at 350° F (175° C) until cooked (about 40 minutes). Remove and allow to cool somewhat. Shred chicken with a fork.
In large bowl mix shredded chicken, 2 cans enchilada sauce, 2 cups cheese, the cilantro (chopped) and 3/4 cup of the chopped green onion.
In a separate bowl, add 1 1/2 cans of the enchilada sauce and microwave 30 seconds to warm. This will be used to soften the tortillas to prevent breakage.
Place about 6 corn tortillas into the sauce (one at a time) for a minute or two to soften.
Place enough chicken mixture to make each enchilada about thumb thick. Pour one can of sauce into two glass rectangular cake pans and spread evenly (helps prevent sticking).
Place rolled enchiladas in the pans lengthwise, about 10 per pan. Take any remaining sauce and spoon over tops of enchiladas thinly. Sprinkle last 1/2 cup cheese lightly over the enchiladas. Top with last 1/4 cup of green onion.
Bake in 350° F oven approximately 35 minutes or until lightly browned.
There are 165 calories in 1 serving of Green Chicken Enchiladas.