Preheat oven to 375 degrees F (190 degrees C). Line cookie sheets with aluminum foil or baking parchment.
Steam raisins in a vegetable steamer over shallow water in a saucepan. Boil water for 3 minutes, until raisins are moist. Remove raisins and let dry on cloth.
In a large bowl, cream together the butter, sugar and vanilla until smooth. Beat in eggs and sour cream until well blended. Sift together flour and baking soda; stir into the butter mixture. Mix in raisins, nuts and chocolate. Drop dough by tablespoons 2 inches apart on cookie sheets.
Bake 13 to 15 minutes, until lightly colored. Let cool on wire racks.