In a large pot, heat the olive oil over medium heat. Sauté the sliced onions until they are soft and translucent, about 5 minutes.

Add the minced garlic to the pot and cook for another minute.

Add the chicken thighs to the pot and season with salt, pepper, cumin, and oregano. Brown the chicken on all sides for about 5 minutes.

In a blender, combine the chipotle peppers and chicken broth. Blend until smooth.

Pour the blended sauce over the browned chicken in the pot. Stir to combine.

Cover the pot and reduce the heat to low. Let it simmer for about 25 minutes, or until the chicken is fully cooked and tender.

Once cooked, remove the chicken from the pot and shred it using two forks.

Add the shredded chicken back into the pot and stir it into the sauce. Allow it to cook for an additional 5 minutes.