In a heavy pot, cook onions, bell peppers and garlic in oil over moderate heat, stirring until the onions just begin to brown.
Add tomatoes with juice, broth, red pepper flakes and black pepper. Simmer about one hour uncovered.
Add rice and simmer for 15 minutes or until rice is tender.
Add chicken and peanut butter, stirring until the soup is smooth and stir in salt to taste.
Enjoy!