In a Dutch oven, heat 1 tablespoon olive oil over medium heat. Add the sliced onion and saute until soft 4-5 minutes. Add the minced garlic and cook until fragrant, another minute or so.
To the pot add the chipotle peppers, chile powder, cumin, oregano and diced tomatoes. Stir until incorporated. Add the chicken broth and season with salt and pepper and simmer for about 5 minutes.
Add the chicken to the pot and stir it together to incorporate the flavors. Turn the heat to low and cook the chicken in the sauce for 7-8 minutes so that the flavors infuse the chicken.
Taste for seasoning and adjust as needed with extra salt and pepper.
In a small bowl, combine the two avocados, then season with salt and pepper and a squeeze of fresh lime juice.
Heat the corn tortillas over an open flame on a gas stove, or in a small non-stick skillet to warm them.
Layer the smashed avocado, then the chicken tinga and top with crumbled cotija cheese, fresh cilantro, diced red onion and jalapeno.
Serve with a salad, rice, or a side of black or refried beans for a delicious Mexican dinner the whole family will love.