Creamy White Chili

1 pound boneless skinless chicken breasts,
    cut into 1/2-inch pieces
1 medium onion, chopped
1 1/2 teaspoons garlic powder
1 tablespoon vegetable oil
2 (15 1/2 ounce) cans great northern beans, rinsed and drained
1 (14 1/2 ounce) can chicken broth
2 (4 ounce) cans chopped green chiles
1 teaspoon salt
1 teaspoon ground cumin
1 teaspoon dried oregano
1/2 teaspoon pepper
1/4 teaspoon cayenne pepper
1 cup sour cream
1/2 cup whipping cream

In large skillet, saute chicken, onions and garlic power in oil until chicken is no longer pink. Add beans, broth, chiles and seasonings. Bring to a boil. Reduce heat; simmer, uncovered, for 30 minutes. Remove from heat; stir in sour cream and cream. Serve immediately.