In a bowl combine sour cream, milk, chile 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. Discard remaining sour cream mixture. Add chicken pieces to flour, 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 (350 degree F). Reduce heat. Carefully add chicken to the skillet. Cook, uncovered, over medium heat about 40 minutes or until chicken is no longer pink (170 degree F for breasts; 180 degree F for thighs and drumsticks), turning occasionally to brown evenly. Drain on paper towels. If desired, serve with bottled hot pepper sauce and lime wedges. Makes 4 to 6 servings.