Boil the chicken breast with a piece of onion, salt, and garlic until cooked through.

For the sauce: Cook the tomatillos and chiles in boiling water for 10 minutes, then remove from heat and set aside.

Preheat the oven to 480°F (250°C). Grease a large baking sheet with butter to prevent sticking.

Blend the chiles, tomatillos, 1 garlic clove, 1/2 onion, cilantro, 2 tablespoons sour cream, and 1/2 tablespoon chicken bouillon powder until smooth.

Fry the sauce in a skillet with 1 tablespoon of oil.

Shred the cooked chicken breast.

Place some shredded chicken in each tortilla and roll it up like a taco. Arrange them on the baking sheet.

Pour the sauce over the enchiladas and sprinkle with shredded cheese.

Bake for 15 minutes or until the cheese is completely melted.