Chicken Enchiladas in Creamy Avocado Sauce

~1¼ lbs. tomatillos, husked & rinsed

Poblano

jalapeño, stemmed

fat cloves garlic, unpeeled

small onion, cut in half

~½ tsp. salt

chicken stock or water

large avocado, peeled & pitted

crema or sour cream

cooked, shredded chicken thighs (or breast or a mix)

corn tortillas (or small flour tortillas)

shredded Monterey Jack cheese

thinly sliced onion

chopped cilantro

cubed avocado

salsa verde