Dice the bell peppers, carrots, celery. Chop the tomatoes and mince the garlic.
Heat the olive oil in a large pot over medium high heat. Toss in onion and sauté for about 3 minutes. Add in the garlic and sauté for 1 minute. Add the chilli powder, cumin and oregano. Stir for about 30 seconds.
Transfer the peppers, carrots and celery into the pot and cook for about 5 minutes or until they just start to soften. Pour the tomatoes with their juice into the pot and bring to a simmer.
Once the chilli begins to simmer, reduce the heat to medium low. You want the chilli to be at a low simmer with the lid off.
Continue to cook the chilli, stirring occasionally, for 20 minutes. Add the beans and corn. Cook for 5 more minutes or until the corn and beans have heated through.