Preheat oven to 425 degrees F. Line a baking sheet with foil and place an oven-safe rack on top.
Using a coffee grinder, food processor or magic bullet, lightly grind macadamia nuts. You could also just place them in a Ziploc bag and use a mason jar to manually crush them. I recommend leaving the nuts still a little chunky. Pour into a bowl. Add whisked egg to a separate bowl.
Dunk chicken cutlets into egg wash to fully coat, and then place them in crushed nuts, evenly coating both sides. Place chicken on rack and place baking sheet in the oven for 23-25 minutes, depending on thickness of chicken. During the final 3 minutes, turn broiler to HIGH to allow the chicken to crisp up.
While the chicken bakes, prepare salsa by combining all ingredients in a medium-sized bowl. Let sit at room temperature until chicken is ready to serve.
To assemble: transfer chicken to a plate and top with 2-3 tbsp of fresh salsa, Optional garnish: lime, fresh mint.
If using unsalted macadamia nuts, season chicken cutlets with sea salt before dipping in egg wash. Baking time may vary depending on thickness of chicken.