Step 1

Heat the oil in a large, heavy-bottomed pot over high. Add the cabbage, season with a large pinch of salt and cook, occasionally stirring, until softened, lightly charred in spots and smelling smoky, about 10 minutes. Add the sweet potato, onion, garlic and another pinch of salt and cook, stirring frequently, until the onion and garlic have softened, about 5 minutes.

Step 2

Stir in the tortilla chips. Add the tomato purée and chipotles and bring to a simmer.

Step 3

Add 5 cups of water and another large pinch of salt; bring to a boil. Reduce the heat to maintain a simmer and cook, stirring occasionally, until the soup is thickened and the sweet potatoes are cooked through, about 15 minutes.

Step 4

Stir in the pinto beans; season to taste with salt and pepper.

Step 5

Divide soup among bowls and serve with desired toppings.