Combine milk, egg, tapioca and salt in a medium saucepan. Let stand for 5 minutes.
Place the saucepan over medium-low heat and cook, stirring constantly, until the mixture comes to a boil, 6 to 18 minutes (depending on your stove). Remove from the heat; stir in 1/4 cup syrup and vanilla.
Divide the pudding between 2 ramekins or custard cups. Let cool for at least 30 minutes or refrigerate until chilled.
Meanwhile, line a small plate with parchment or wax paper. Coat the paper with cooking spray. Combine walnuts, the remaining 1 tablespoon syrup, cinnamon and nutmeg in a small saucepan or skillet. Heat over medium-low heat, stirring, until most of the syrup has evaporated, 1 to 4 minutes. Spread the nuts out onto the prepared paper and place in the freezer until cool, about 10 minutes.
Crumble the chilled walnut topping into pieces. Serve the pudding topped with the maple walnuts.