Preheat the oven to 375 degrees F (190 degrees C). Wrap sweet potato in aluminum foil.
Bake sweet potato in the preheated oven until easily pierced with a fork, about 1 hour. Set aside to cool.
Whisk white sugar and canola oil together in a bowl. Add eggs; mix well. Sift flour, cinnamon, and nutmeg into sugar mixture. Slowly whisk water into flour-sugar mixture until incorporated.
Peel sweet potato; mash into the batter. Fold in 1/2 cup chopped pecans.
Reduce oven temperature to 320 degrees F (160 degrees C). Spray a 9x5-inch loaf pan with cooking spray.
Pour batter into the prepared loaf pan.
Bake in the preheated oven until a toothpick inserted in the center of bread comes out clean, about 1 hour.
Heat brown sugar and butter in a small saucepan over low heat until sugar is dissolved, about 5 minutes. Add 1/2 cup chopped pecans and stir to combine. Remove from heat. Pour glaze over bread.