Finely chop the onion, mince the garlic, and grate the tomatoes.
In a large pot, saute the onion with 2 tablespoons of cooking oil for like 3 to 5 minutes on medium-high heat. Then add a tablespoon of minced garlic and saute for 2 more minutes or just until it's fragrant.
Add the grated tomatoes and cook for 3 minutes with the pot uncovered.
Add the chicken breasts as they are, add 2 tablespoons of chipotle paste, 1 bay leaf, thyme sprig, and oregano as well as 2 cups of chicken broth, and cook for 15 minutes.
Remove from heat then take out the chicken breasts and shred them on a chopping board with 2 forks.
Your chicken tinga soup is ready to be enjoyed