Heat oil in 4-quart pot over medium heat. Add onion, garlic and chili powder; saute for 5 minutes. Add green and red peppers; saute 5 minutes. Add zucchini, squash, oregano and ground red pepper; saute for 5 minutes. Add tomatoes; cook 10 minutes. Stir in corn, black beans and salt; cook for 5 minutes.

Serve with the accompaniments, if desired.

3 ripe avocados, peeled and pitted

3 tablespoons finely chopped red onion

3 tablespoons fresh-squeezed lime juice

2 tablespoons chopped cilantro leaves

1 jalepeno, seeded and minced

1/4 teaspoon salt

1/4 teaspoon hot pepper sauce

Mash avocado flesh in a bowl. Stir in red onion, lime juice, cilantro, jalapeno, salt, and hot-pepper sauce. Refrigerate. Spoon a dollop on each chili serving.