Line a 9×5 inch loaf pan with parchment or waxed paper. Set aside about 10 of the macadamia nuts and use a sharp knife to chop them finely.
Place the remaining macadamia nuts in a food processor and grind until they start to release their oils and become a nut butter. You will have to scrape down the blade and sides of the processor multiple times.
Add the protein powder, almond flour, sweetener, vanilla, and salt. Continue to process until well mixed, scraping down the sides as needed.
At this point, the mixture will be quite dry. Add 1/4 cup of the water and continue to process until the mixture begins to clump together. Add more water as needed, a little at a time. Once you can squeeze the mixture together in the palm of your hand, it’s ready.
Transfer to a bowl and stir in half of the white chocolate chips and chopped nuts. Press the mixture into the prepared pan firmly and evenly. Refrigerate about an hour to firm up.
Lift out by the edges of the parchment and slice into 8 bars.
In a small microwave-safe bowl, combine the remaining white chocolate chips and the coconut oil. Melt on high in short bursts, stirring frequently until smooth. Drizzle over the bars.