Preheat the oven to 375 degrees F (190 degrees C). Lightly grease cookie sheets.

In a large bowl, mix together the canola oil, margarine, brown sugar and white sugar until smooth. Beat in the eggs one at a time, then stir in the vanilla. Combine the flour, baking soda, baking powder and salt; stir into the sugar mixture. Mix in the cornflakes cereal, oats, chocolate chips and walnuts. Drop by heaping teaspoonfuls onto the prepared cookie sheets.

Bake for 12 to 15 minutes in the preheated oven, until golden brown. Allow cookies to cool slightly on the cookie sheets before removing to wire racks to cool completely.