In a large pot, cook the chicken with garlic, onion, bay leaves, oregano, salt, and water or chicken stock until tender (about 30-40 minutes). Shred the chicken once cooked.
In a separate pan, heat oil and sauté sliced onions and garlic until soft and golden.
In a blender, combine tomatoes, chipotle chiles in adobo, oregano, thyme, marjoram, salt, and black pepper. Blend until smooth.
Add the chipotle sauce to the pan with the onions and garlic. Simmer for 5-10 minutes.
Add the shredded chicken to the pan and mix well, simmering for another 5 minutes until well-coated in the sauce.
Adjust seasoning to taste and serve hot.