1. To make the crust, place the cereal in the bowl of a food processor or blender, and process into fine crumbs. Measure the crumbs. There should be 1/4 cups. (Adjust the amount if necessary.)
2. Return the crumbs to the food processor. Add the fruit spread, and process until the mixture is moist and crumbly.
3. Coat a 9-inch pie pan with nonstick cooking spray, and use the back of a spoon to press the crumbs against the sides and bottom of the pan, forming an even crust. (Periodically dip the spoon in sugar, if necessary, to prevent sticking.) Bake at 350° F for 10 minutes, or until the edges feel firm and dry. Set aside to cool.
4. To make the glaze, place the sugar and cornstarch in a small saucepan, and stir to mix well. Slowly stir in the nectar. Place the saucepan over medium heat, and bring the mixture to a boil, stirring constantly. Reduce the heat to low, and cook and stir for another minute. Remove the saucepan from the heat, and set aside for 15 minutes.
5. To assemble the pie, stir the glaze and spoon a thin layer over the bottom of the crust. Arrange half of the peach slices in a circular pattern over the glaze. Top with the blueberries or raspberries and half of the remaining glaze. Arrange the rest of the peaches over the glaze, and top with the remaining glaze. Chill for several hours, or until the glaze is set.