White Chili with Chicken

1 lb boneless chicken
1 medium chopped onion
1 1/2 teaspoons garlic powder (or one fresh clove)
1 tablespoon vegetable oil
31 oz great northern beans -- rinsed and drained
14 1/2 oz chicken broth
8 oz chopped green chiles
1 teaspoon salt
1 teaspoon ground cumin
1 teaspoon oregeno
1/2 teaspoon pepper
1/4 teaspoon cayenne pepper
1 cup sour cream
1/2 cup whipping cream

Saute chicken, onion, garlic in oil until chicken is no longer pink. Add beans, broth, chilies, & seasonings. Bring to boil. Reduce heat; simmer, uncovered for 30 minutes. Remove from heat and add sour cream and whipping cream.