In large bowl, combine margarine, confectioners' sugar, condensed milk, coconut, chopped walnuts and vanilla. Stir well. Cover and chill in the refrigerator for 2 hours, or until mixture has thickened enough to roll into balls. Roll the mixture into 1-inch balls and place close together, but not touching, on cookie sheets. Freeze until hard.
While bonbons are freezing, line a cookie sheet or flat surface with waxed paper. Combine chocolate chips and shortening in the top of a double boiler, over, not in, simmering water. Stir until melted. Using a toothpick or a fork, dip each bonbon in the melted chocolate. Place on waxed paper to dry. When chocolate has hardened, store bonbons in plastic bag in the freezer.