Preheat oven to 180 degrees C. Grease a 20x30cm baking dish.
In a large saucepan, bring the water to a boil. Remove from the heat and add the quick oats. Cover and let stand for a few minutes, until the water is absorbed. While still warm, stir in the butter, white sugar and brown sugar. Mix until the butter is melted then stir in the eggs. Combine the flour, bicarb soda, salt and cinnamon, stir into the oatmeal mixture. Fold in the coconut, 1 cup of the chocolate chips and the nuts. Pour into the prepared pan and sprinkle the remaining chocolate chips over the top.
Bake for 35 minutes in the preheated oven, until the cake springs back when lightly touched.