Heat a large pot over medium high heat and add a bit of oil or vegetable broth. Add onion, carrots, and garlic and cook until the onions turn translucent.
Add zucchini and bell pepper and cook for 1-2 minutes. Add a splash of vegetable broth as needed to prevent the veggies from sticking.
Add the spices and stir to combine with the veggies.
Stir in tomato paste, tomato sauce, sweetener, and 2 cups vegetable broth. Bring to a boil then lower to simmer, covered, for 20 minutes. Stir occasionally to prevent sticking to the bottom of the pan.
Add in black beans and continue simmering for another 10 minutes, or until thickened and veggies are tender. Add more vegetable broth if the chili looks too thick for your liking.
Finally, add in lemon juice, cilantro, and salt/pepper to taste.