Preheat a large deep skillet over low to medium heat and swirl in oil to coat the pan.
Add chopped onion, garlic, and bell peppers; sauté for 3 minutes, stirring occasionally.
Push vegetables to the side and add chicken pieces; season with 1 teaspoon cumin, salt, and black pepper.
Cook chicken for about 5 minutes, stirring occasionally until partially cooked.
Add corn, black beans, diced tomatoes (with juice), zucchini, taco seasoning, and remaining cumin; stir well.
Cover and cook over low to medium heat for 10 minutes until vegetables are tender but not soft.
Sprinkle shredded cheese over the top; cover and cook a few more minutes until cheese melts.
Garnish with chopped green onions and cilantro before serving.
Serve hot alone or with brown rice, quinoa, sour cream, avocado, or crushed tortilla chips as desired.