Line a square 9+9baking pan with foil, leaving the ends overlapping the edges so you can lift the toffee out when it has set for easier cutting

Put the Butter,sugar,corn syrup and water in a heavy saucepan bring to a boil over medium heat, stirring constantly to dissolve the sugar

Gently boil the mixtur, stirring constantly, until it darkens in color and reaches 30 of on a candy thermometer

Remove from the heat and stir in the chopped walnuts. Pour the hot candy into the prepared pan. Smoothing our with a spatula,Be very careful as this is very hot.

Scatter the chocolate chips evenly across the surface of the toffee and let sit for a couple of minutes to let the chocolate melt. Spread the chocolate out evenly wit a spreader. Then top with chopped nuts.
Pressing them in gently so they will stick to the chocolate

Let cool until set either at room temperature, or in the refrigerator.

Remove the foil and cut into pieces