Mix the sugar, margarine and eggs for 3 minutes. Add the flour, baking powder, baking soda, salt, walnuts and mashed bananas. Mix together until all ingredients are well incorporated. Add the chocolate chips and stir to mix.
Grease a regular size loaf pan. Pour the batter into the loaf pan and bake for 1 hour or until a toothpick inserted into the center comes out clean.