Butterfly the chicken breast and pound it to an even half-inch thickness for uniform cooking.
In a shallow bowl, whisk the egg until smooth.
In a second shallow bowl, combine the parmesan cheese, almond flour, garlic powder, sea salt, and black pepper.
Dip the chicken breast into the egg wash, then dredge it through the parmesan mixture, pressing firmly to ensure a thick crust.
Heat the olive oil in a large non-stick skillet over medium heat.
Add the chicken to the skillet and cook for 5 to 6 minutes per side until the crust is golden brown and the internal temperature reaches 165 degrees.
While the chicken cooks, warm the marinara sauce in a small saucepan over low heat.
Remove the chicken from the skillet and let it rest; add the zucchini noodles to the same skillet and sauté for 2 minutes until just tender.
Place the zucchini noodles on a plate, top with the crispy chicken, and finish with the warm marinara sauce.