Cream together the butter, caster sugar and brown sugar until smooth. Beat in the eggs one at a time, then stir in the vanilla. Dissolve bicarbonate of soda in hot water. Add to batter along with salt. Stir in flour, chocolate chips and nuts. Drop by large spoonfuls onto ungreased baking trays.
Bake for about 10 minutes in the preheated oven, or until edges are nicely browned.