Preheat the grill. Line a baking tray with aluminium foil.
Combine macadamia nuts, soy sauce, garlic, hot sauce, brown sugar, olive oil and black pepper in a food processor; blend until the mixture is the consistency of paste.
Spoon a thick layer of the macadamia mixture on top of each fillet. Place the fish macadamia mixture-side up on the prepared baking tray. Under the grill cook fish until the macadamia crust is golden brown and the fish flakes easily, about 15 minutes.