Wash and disinfect the vegetables well, peel and grate the carrots and slice the zucchini and onion into stripes.
Heat a little oil in a saucepan and sauté the onion over medium heat until it turns transparent.
Add the zucchini, carrot and a little salt, stir and cook over low heat with the lid on for 5 to 10 minutes, just make sure it doesn't dry out.
Blend the tomatoes, garlic, veggie broth, onion and chipotles and add to the stew and cook over low heat for another 15 minutes.
Add salt and pepper to taste and serve on nixtamalised corn tostadas, accompanied by slices of radish and avocado.