Preheat the oven to 375°F (190°C). Spray a baking sheet with cooking spray and set it aside.
Place the macadamia nuts and shredded coconut in a food processor and pulse until finely ground but not oily.
Add the panko crumbs to the food processor and give the mixture a quick pulse just to combine. Pour the coconut–macadamia–panko mixture onto a plate or shallow dish.
Put the all-purpose flour on a separate plate or shallow dish.
In a bowl, whisk together the egg and the milk until combined.
Sprinkle the chicken tenders with salt and pepper on both sides. Working with one tender at a time, lightly coat it in the flour, shaking off any excess; dip it into the egg–milk mixture; then press and roll it in the coconut–macadamia–panko mixture so it is well coated. Place each coated tender on the prepared baking sheet, leaving a little space between pieces.
Lightly spray the tops of the coated chicken tenders with cooking spray.
Bake in the preheated oven for about 15 minutes, or until the chicken is cooked through and no longer pink in the center (internal temperature 165°F / 74°C if using a thermometer).
While the chicken bakes, combine the red pepper jelly, finely diced fresh peach, Creole mustard, and horseradish in a small saucepan. Bring to a gentle simmer over medium-low heat, stirring occasionally, and simmer for 5 minutes.
Remove the sauce from the heat and let it cool to room temperature before serving with the baked coconut macadamia chicken tenders.