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 in flour, cinnamon, and nutmeg. Slowly whisk in water until incorporated.

Peel sweet potato; mash flesh into batter. Fold in 1/2 cup chopped pecans.

Reduce the oven temperature to 320 degrees F (160 degrees C). Coat a 9x5-inch loaf pan with cooking spray.

Pour batter into the prepared loaf pan.

Bake in the preheated oven until a toothpick inserted into the center 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. Stir in remaining 1/2 cup chopped pecans to combine. Pour brown sugar-pecan glaze over bread.