Mix together walnuts, brown sugar, flour and melted butter in a small bowl. Set aside.
Preheat oven to 350°F
In a large bowl, whisk together eggs, applesauce, oil, vanilla, and cinnamon.
Add in grated zucchini and stir to combine.
In a medium bowl, whisk together flour, salt, baking soda, and baking powder.
Stir the dry ingredients into the wet ingredients until only a few streaks of flour remain. Stir in the chocolate chips until everything is well combined.
Grease a bundt pan very well with a neutral oil or cooking spray, and then lightly flour the pan.
Fill the bundt with half the batter, then sprinkle with the streusel. Top with remaining batter.
Bake for 50-60 minutes, or until a toothpick comes out clean. Let cool for 10 minutes, then remove cake from the pan, and transfer to a cooling rack.
Heat the cream in a small saucepan until just simmering. Pour over chocolate and allow to sit for 1-2 minutes. Add in the corn syrup. This will help the glaze stay shiny. Whisk until smooth.
Allow the ganache to cool at room temperature for about 10 minutes, then whisk vigorously until it thickens and coats the back of a spoon. You want the ganache to be thick enough to have a good layer on the cake, but thin enough to still drizzle down slowly.
Pour over a cooled bundt cake and garnish with chopped walnuts.