Preheat oven to 350°F (177°C). Grease a 9x5-inch loaf pan with nonstick cooking spray. In a medium bowl, whisk together flour, cocoa powder, baking soda, and sea salt until free of lumps.

In a large bowl, whisk together eggs, melted butter, oil, vanilla, and brown sugar until smooth and pale. Small sugar clumps are fine.

Add shredded zucchini to the wet mixture and stir gently until evenly distributed.

Fold the dry ingredients into the wet mixture using a gentle 'J' motion until just combined. Avoid over-mixing.

Fold in 3/4 cup of semisweet chocolate chips gently with 2-3 turns of the spatula.

Pour batter into the prepared loaf pan, smooth the top, and sprinkle the remaining 1/4 cup chocolate chips over the surface.

Bake for 50-60 minutes, or until a toothpick inserted into the center comes out mostly clean. Cool in pan for 15 minutes, then remove and cool completely before slicing.