Preheat the oven to 350°F. Coat a 10-inch Bundt pan with nonstick spray.
In a small bowl, whisk together the flour, baking soda, salt, nutmeg, pudding mix, and cocoa powder.
In the bowl of a stand mixer fitted with the paddle attachment, cream the brown sugar and butter until light and fluffy, about 3 minutes. Add the canola oil and eggs and beat until smooth.
In a medium bowl, whisk half the melted chocolate chips and the buttermilk until well blended. Whisk in the moonshine, rum, orange zest, and 1/4 cup plus 2 tablespoons water until smooth.
Add the flour mixture to the butter mixture in three additions, alternating with the buttermilk mixture and beginning and ending with the flour; beat on medium speed until just blended and smooth after each addition.
Transfer the batter to the prepared pan. Smooth the top with a spatula. Bake for 45 minutes, turning the pan after 20 minutes, until a toothpick inserted into the center of the cake comes out clean. Let cool completely, then turn the cake out of the pan onto a cake platter or plate.
Drizzle the remaining 1/2 cup melted chocolate over the top of the cake (reheat it briefly if it has set too much to drizzle), letting it run down the sides.