Wash and pat dry chicken. Rub onion soup mix liberally over chicken. Place in dish. Cover and refrigerate over night. Next morning, place chicken in a crock-pot and pour salsa over the top of the chicken. Stir around a bit to get the salsa over all pieces of chicken. Cook on low for 8 hours. Remove chicken from crock-pot and shred for tacos, burritos, or enchiladas. May also be used as a topper for mashed potatoes, rice, or noodles.