First, gather six to eight 1-inch-thick hardcover books and wipe the spines and covers clean (you could also cover them in parchment paper). Set them up vertically, spine up, so that they can be your taco shell molds.
For the taco shells: To make the taco shell batter, whisk together the flour, sugar and salt in a medium bowl. Add the melted butter to a separate bowl and whisk in the milk, vanilla extract and almond extract. Then whisk in the egg whites. Add the wet ingredients to the dry ingredients and mix to form a smooth batter.
To cook the shells, heat a skillet over medium heat. Grease it with butter and then spoon in 2 1/2 tablespoons of batter. Spread it out gently with the back of a spoon or offset spatula so you have an even circle. Cook until slightly brown on the bottom, 3 to 5 minutes. Flip and cook until slightly brown on the second side, 1 to 2 more minutes. Remove it from the skillet and gently fold it over the spine of the book to make a taco shell shape. Let cool on the book. Repeat with the remaining batter.
For the fillings and toppings: To make the chocolate topping, place the chocolate chips and coconut oil in a microwave-safe bowl. Microwave in 30-second increments, stirring after each, until melted. Let the chocolate cool slightly before topping the tacos.
Let the ice cream soften a bit, fill the taco shells, drizzle with as much chocolate as you wish, top with nuts and enjoy! If you're making these in advance, stick them in the freezer, uncovered, for a few minutes until the chocolate hardens, and then wrap in plastic wrap and freeze until you're ready to eat them.