Put all ingredients into a sauce pan, except onion. Cover with water and bring to a boil. Simmer for about 15 min.
Remove all solids and discard the water, reserving 1 cup.
Return solids and water back to pot with the diced onion.
Using an immersion blender (or blender or food processor), puree until a smooth thickened stock is formed. Reserve for later.
Add olive oil and onions to pot, let soften on low-medium heat ~ 10-15 min., stirring occasionally
Add garlic and stir for 30 sec. Then start adding one by one to allow a slow softening and blending of all the veggies. This is why I don't prep ahead for this b/c there is time in between to allow for the softening.
Once all veggies are added, add in the beans, corn, diced tomatoes, spices and herbs, then add the tomato stock. You may add more water, vegetable, or chicken stock here to thin things out for a soup consistency.
Bring to a boil, then let simmer for 30-60 min. stirring occasionally.
Once off the heat, add rotisserie chicken and stir. If chicken is added to soon while on simmer, it can break down too much losing the shredded or diced feel.
Serve with tortilla chips, cheddar cheese, avocado, sour cream, etc.