Mexican Vegetable Soup - cooking recipe

Ingredients

1 Tbsp. vegetable oil
1 large onion, chopped
1 (14 oz.) can chicken broth
2 c. water
1 (28 oz.) can whole tomatoes
2 medium zucchini, scrubbed and cut into cubes
3 medium potatoes, scrubbed and cut into cubes
1 (10 oz.) pkg. fresh tomatillos*
1 (15 oz.) can pinto beans or red kidney beans
1 (16 oz.) pkg. frozen corn
1 1/2 tsp. ground cumin
1 tsp. chili powder or to taste
1/2 tsp. oregano
salt and black pepper to taste
1 handful tortilla chips, crushed (for garnish)

Preparation

*They look like small green tomatoes with papery husks and sometimes can be found in supermarkets.
Omit them if unavailable.