Pour butter over oats; mix thoroughly. Add sugar, syrup, salt and vanilla; blend well. Firmly pack into well-greased 11 x 7-inch metal baking pan. Bake in preheated very hot oven (450 F.) about 12 minutes. (Mixture will be brown and bubbly.) Cool thoroughly. Loosen edges; invert pan and tap firmly against bread board or cutting board. Spread with chocolate. Sprinkle with nutmeats. Chill; cut in small bars. Store in refrigerator.