Slow Cooker White Chicken Chili

1 medium onion, chopped
2 cloves garlic, chopped
1 ½ to 2 cups cooked chicken breast
1 14.5-ounce can cannellini beans, rinsed and drained
1 cup homemade chicken stock
1 4-ounce can chopped green chilies
½  teaspoon kosher salt
1 teaspoon ground cumin
1 teaspoon dried oregano
¼  teaspoon Melissa’s Green Hatch Chile powder
½  teaspoon freshly ground black pepper
Pinch of cayenne pepper
2/3 cup sour cream

Place all ingredients except the sour cream into your slow cooker, stir to combine . Cover and cook on low 5 to 6 hours. Stir in sour cream, and allow to heat through, about 15 minutes. Serve garnished as you see fit.