Grate the zucchini and place in a sieve in the sink. Sprinkle with ¼ teaspoon salt and toss to combine. Let drain 1 hour, then squeeze out as much moisture as possible.
Preheat the oven 350F and line two muffin pans with 16 silicone or parchment paper liners. (If you do not have two muffin pans, you can do this in batches, or you can bake the remaining muffin batter in greased ramekins).
In a large bowl, whisk together the almond flour, sweetener, cocoa powder, protein powder, baking powder, and the remaining salt.
Stir in the eggs, oil and zucchini until well combined. Stir in the coffee or water, and stir until well mixed. If your batter is very thick, add a little more liquid, one tablespoon at a time, until it reaches a thick pourable consistency.
Stir in the vanilla extract and ⅓ cup of the chocolate chips. Divide the batter evenly among the prepared muffin cups, and sprinkle the tops with the remaining chocolate chips.
Bake 25 to 30 minutes, until the muffins have risen and the tops are firm to the touch. Remove and let cool complete in the pan.