In a large heavy bottomed pot, heat the olive oil over medium high heat. Add the onion,
celery and carrots. Sauté until the onions have softened, then add the garlic. Cook for a minute then add the cumin and thyme. Stir for a second until fragrant, then add the chipotle and jalapeño. Cook one more minute then add the broth and the tomatoes. Bring to a boil, then reduce the heat to medium and simmer for about 20 - 25 minutes.
Add the black beans and continue to simmer for another 5 minutes.
Just before serving, add the tortilla strips and the handful of cilantro or parsley, give it a stir and removed the pot from the heat. Allow to sit for a few minutes while you prepare the toppings.
Preheat your oven to 375 degrees. Place the tortilla that you cut into fine strips on a baking sheet, brush with some olive oil and a sprinkling of salt. Toss to coat and bake for 4 to 5 minutes or until just golden and crisp.
To serve the soup, put some of the shredded chicken (if using) at the bottom of the bowl, ladle the soup over the chicken, top with the avocado cubes, a squeeze of lime, the Cotija crumbles, some crunchy strips of tortilla then add a bit of lime zest and more cilantro or parsley if desired.