1For the Salsa Verde, place tomatillos, jalapeno and onion in medium saucepan. Fill with just enough water to cover tomatillos. Bring to boil on high heat. Reduce heat to low; cover and simmer 10 minutes. Using a slotted spoon, transfer tomatillos, jalapeno and onion to blender container. Add cilantro, Garlic Powder, lime juice and salt. Cover. Blend on high speed until smooth. Add crema; pulse just until blended.
2For the Enchiladas, preheat oven to 350°F. Spray 13x9-inch baking dish with no stick cooking spray. Spread 1 cup of the Salsa Verde mixture evenly into bottom of dish. Set aside.
3Mix shredded chicken, 1 cup of the cheese, Garlic Powder, salt and Pepper in medium bowl. Place about 1/3 cup of the chicken mixture down the center of each warmed tortilla. Roll to enclose filling and place seam side down in baking dish. Pour remaining Salsa Verde mixture evenly over enchiladas. Sprinkle evenly with remaining 2 cups cheese.
4Bake 30 to 35 minutes or until heated through cheese is lightly browned. Let stand 10 minutes before serving. Sprinkle with thinly sliced red onion and chopped fresh cilantro, if desired.