In a large Dutch oven, melt 4 tablespoons of butter over meadium=high heat.

Cut chicken up into bite sized pieces and brown in butter until nicely colored and cooked through. Remove chicken from pan.

Add remaining butter to pan, stir in flour. This will make a roux. 

Stir in sliced onions and pepper. Add chicken stock to deglze the pan and stir in heavy cream. I use half and half or you can use even thicker cream.  Lower heat and cook until the mixture thickens.

Once thickened, add chili powder, pepper and salt. Stir and cook a few minutes then add in northern beans, chilies and the chicken.