Creamy White Chicken Chili

I have seen this recipe, or versions of it, everywhere on the web.  I finally decided to try it after reading about all these people winning first place in chili contests.  I was really impressed.  It was a delicious alternative to traditional chili and I loved the creamy taste of the sour cream stirred in at the end.  My kids liked it but it was a little spicy for them.  Next time I will cut the cayenne down to an 1/8 tsp. and add only one can of chilies. 

3-4 Chicken breasts or a combination of breasts and thighs (I cooked mine in the crock pot earlier in the day.)
2 Cans Great Northern beans
2 Cans Chopped Green Chilies
1 Can Chicken Broth
1 1/2 tsp. Garlic Powder
1 Large Onion, chopped coarsely
1 T. Olive Oil
1 tsp. Cumin
1 tsp. Oregano
1 tsp. Salt
1/2 tsp. Pepper
1/4 tsp. Cayenne Pepper
1 C. Sour Cream
1/2 C. Heavy Cream (you could also use half and half or, in a pinch, just regular milk)

If you have cooked your chicken ahead, shred it and set it aside.  Saute the onion in oil until translucent.  If not then cut the chicken into bite sized pieces and transfer to a soup pot.  Add onion, garlic powder and oil then cook on medium high heat until chicken is cooked through. Add all ingredients to pot except sour cream and whipping cream.  Simmer on medium low for 30 minutes.  Add sour cream and heavy cream to pot and stir until all the sour cream is dissolved into broth.