Place the chicken breast in a pot with water and cook for 30-40 minutes. While the chicken is cooking, you can start making the sauce.

Wash the tomatillos, onion, garlic, and serrano peppers thoroughly. Place them in a pot with water and cook until they turn a darker color. For a spicy sauce, use 8 to 10 peppers, or adjust to your taste.

Transfer the cooked sauce ingredients to a blender and blend until smooth. Add a little water, or use some of the chicken cooking broth if you prefer.

Pour the blended sauce back into the pot, add the chicken bouillon cube and salt to taste. You can also add a pinch of cumin if you like. Bring to a boil, then the sauce is ready.

Once the chicken is cooked, shred it.

Lightly fry the tortillas in a little oil, then dip them in the sauce. Fill each tortilla with shredded chicken and give them another coating of sauce.

Top with sliced cheese and microwave for about 30 seconds until the cheese melts.

Add sliced onion on top if you like, and enjoy!