Pulse macadamia nuts in a food processor until finely ground. Add breadcrumbs, and pulse 2 or 3 times or until combined. Place nut mixture in a shallow dish.
Place flour in a shallow dish. Whisk eggs in a medium bowl. Sprinkle fish with salt. Dredge fish in flour; shake off excess, and dip in egg. Dredge fish in nut mixture, coating completely.
Heat oil and butter in a large heavy skillet over medium heat until butter melts. Add fish; cook 6 to 8 minutes on each side or until golden. (If nuts begin to brown too quickly, reduce heat.) Serve with Mango-Lime Salsa.