Bring a pot of salted water to a boil and cook the whole wheat spaghetti until al dente, about 8-10 minutes.
In a small bowl, whisk together the egg, parmesan cheese, and black pepper until well combined; set aside.
In a large skillet over medium heat, cook the diced pancetta until it becomes crispy and golden.
Add the cubed chicken breast to the skillet with the pancetta fat and sear until the chicken is cooked through and lightly browned.
Add the minced garlic and zucchini noodles to the skillet, sautéing for just 2 minutes until the zucchini is tender but not mushy.
Drain the pasta, reserving 2 tablespoons of the cooking water, and add the pasta to the skillet with the chicken.
Remove the skillet from the heat entirely to prevent the eggs from scrambling.
Quickly stir in the egg mixture and the reserved pasta water, tossing everything continuously until a smooth, creamy sauce forms.
Season with sea salt and serve immediately while the sauce is warm and glossy.