Spray a baking sheet with non-stick spray, and spread out the chopped pecans, reserving about ½ cup of chopped pecans which are really finely chopped to use on the top at the end.

Melt butter and water in a large heavy saucepan. Add the sugar to the melted butter and water, and stir constantly with a wooden spoon until the sugar is fully dissolved. Occasionally brush the inside of the pot down with cold water, using a pastry brush, to help prevent the candy from recrystallization. Continue cooking and stirring occasionally until the candy turns a dark amber. Be careful not to burn it though.

Pour the candy evenly over the nuts in the prepared pan. Use an offset spatula dipped in cold water so it doesn't stick to smooth the toffee mixture out and completely cover the nuts. Be careful as you work, as it's very hot.

While the candy is still hot, cover completely with chocolate chips. As they melt, use an offset spatula to spread the chocolate layer evenly. Sprinkle the top of the layer of chocolate with the reserved finely chopped pecans. Let it harden, and then break into small pieces. Let set at room temperature. Store in an airtight container.