Mix ingredients for the marinade in shallow pan and place chicken (filleted lengthwise)in pan, turning to coat. Allow to marinade for at lease 20 minutes, longer for better flavor.
Heat oil in skillet, and saute onion, salt, and pepper until onions are translucent. Remove onion temporarily and add chicken breasts to pan and brown on both sides (don't cook chicken all the way through). Remove chicken to a platter and add onions back to the pan along with all ingredients except sugar and parmesan cheese, mixing well. Simmer 30 minutes. Return chicken to the pan and continue to simmer until chicken is done. Add parmesan cheese and sugar for desired sweetness. Serve over linguini.