1Heat oven to 375ºF. In large bowl, beat brown sugar, butter and egg with electric mixer on medium speed, or mix with spoon. Stir in flour, baking soda and salt (dough will be soft). Stir in nuts, 4 ounces bittersweet chocolate, 4 ounces sweet chocolate and 4 ounces white chocolate. Drop dough by rounded tablespoonfuls about 2 inches apart onto ungreased cookie sheet.
2Bake cookies 8 to 10 minutes or until light golden brown. Cool 1 to 2 minutes; remove from cookie sheet to wire rack. Cool completely, about 30 minutes.
3In small saucepan, heat 1 teaspoon shortening and 3 ounces bittersweet chocolate over low heat, stirring constantly, until chocolate is melted and smooth; remove from heat. Repeat with 1 teaspoon shortening and 3 ounces sweet chocolate; repeat with 1 teaspoon shortening and 3 ounces white chocolate.
4Dip 1/2-inch edge of each cookie into each glaze, allowing each glaze to completely set before dipping into next glaze and rotating dipped edge of cookie for each type of glaze. Place cookies on waxed paper to allow glazes to set.