In a bowl combine sour cream, milk, chili peppers, cilantro, lime juice, garlic, cumin, salt, and black pepper.
Place chicken pieces in a bag and set in a shallow dish. Pour sour cream mixture over chicken, seal bag.
Refrigerate overnight, turn bag occasionally.
Place flour in a shallow dish.
Remove chicken from sour cream mixture shaking off excess.
Discard sour cream mixture remaining in bag.
Add chicken pieces to flour mixture, a few at a time, turning to coat.
Add oil to a 12-inch heavy skillet to a depth of 1/4 to 1/2 inch. Heat over medium high heat until hot (350F) Reduce heat.
Carefully add chicken to the skillet. Cook uncovered, over medium heat about 40 minutes or until chicken is no longer pink (170 F for breast, 180F for thighs and drumsticks), turning occasionally to brown evenly.