Heat oven to 350°F. In medium bowl, combine flour, baking soda, cinnamon and salt; mix well. In large bowl, beat butter and sugars with electric mixer until creamy. Add eggs and vanilla; beat well. Add flour mixture; mix well. Stir in oats and, if desired, raisins; mix well. Drop dough by rounded tablespoonfuls onto ungreased cookie sheets. Bake 10 to 12 minutes or until light golden brown. Cool 1 minute on cookie sheets; remove to wire rack. Makes about 4 dozen. Cool completely. Melt chocolate chips according to package directions. Dip half of one cookie in chocolate; gently shake to remove excess. Sprinkle with chopped nuts. Place on waxed paper until set. Repeat with remaining cookies. If chocolate thickens, microwave at 15-second intervals until fluid. Store cookies with waxed paper between layers in tightly covered container.