Prepare the Chicken:

1. Cook Chicken: Heat the vegetable oil in a large skillet over medium heat. Add the chicken thighs and cook until browned on both sides, about 5 minutes per side. Transfer to a plate and let cool slightly.
2. Shred Chicken: Once cool enough to handle, shred the chicken into bite-sized pieces with two forks or your hands. Set aside.

Make the Sauce:

1. Cook Aromatics: In the same skillet, add a little more oil if needed. Add the chopped onion and cook until softened, about 5 minutes. Stir in the minced garlic and cook for another minute.
2. Blend Sauce Ingredients: In a blender, combine the diced tomatoes, chipotle peppers, adobo sauce, dried oregano, and ground cumin. Blend until smooth.
3. Simmer Sauce: Pour the blended sauce into the skillet with the onions and garlic. Bring to a simmer and cook for 5 minutes, allowing the flavors to meld. Season with salt and pepper to taste.

Combine Chicken and Sauce:

1. Simmer Together: Add the shredded chicken to the skillet with the sauce. Stir well to coat the chicken evenly. Pour in the chicken broth and bring to a simmer. Cook for 10-15 minutes, until the chicken is heated through and the sauce has thickened slightly.

Serve:

1. Assemble: Serve the Chicken Tinga in warm tortillas or over rice. Top with shredded lettuce, sliced avocado, crumbled queso fresco, sour cream, chopped cilantro, and lime wedges.