In a large stockpot, heat the olive oil over medium-high heat. Add in the minced garlic and crushed red pepper. Stir for 1 minute until toasty, then toss in the carrots, celery, red pepper, green pepper and green onions. Stir and cook for 10 minutes until softened.
Add in the tomato paste, taco seasoning, chili powder, oregano, garlic powder, onion powder, salt and pepper. Let cook for 1 minutes, then pour in the chicken broth and chicken. Bring to a bowl then lower to a simmer and let cook for 15 minutes.
In a small bowl, mix together the corn starch and water then pour into the pot to thicken the soup. Let cook for another 5 minutes.