With a large knife, cut melon into 8 thick slices. Remove seeds.
Cut off green rind.
Chop macadamia nuts. In a non-stick dry pan over medium heat, toast macadamia nuts and almonds. Let cool.
Rinse lemon balm, shake dry and chop leaves coarsely.
In a small bowl, finely chop cooled nuts and lemon balm with an immersion blender.
Juice lime and measure 2 tablespoons of juice.
In a bowl, combine lime juice with maple syrup, nuts and herbs. Mix well.
In a grill pan over medium-high heat, grill melon slices briefly on both sides. Serve topped with the nut and herb mixture.