Bring a large pot of salted water to a boil and cook the whole wheat spaghetti according to package directions until al dente.
While the pasta cooks, dice the chicken breast into small bite-sized pieces and season lightly with sea salt and black pepper.
In a large skillet over medium heat, cook the diced pancetta until crispy, then remove with a slotted spoon and set aside.
In the same skillet with the rendered pancetta fat, add the chicken breast and cook until golden and cooked through, adding the minced garlic in the last minute.
In a small bowl, whisk together the egg and Pecorino Romano cheese until well combined.
Reserve 0.25 cup of the starchy pasta water, then drain the spaghetti.
Turn off the heat in the skillet, add the pasta and crispy pancetta back to the chicken, and toss to combine.
Slowly pour the egg mixture over the pasta while tossing constantly, adding a splash of reserved pasta water as needed to create a smooth, velvety sauce.
Garnish with chopped fresh parsley and an extra crack of black pepper before serving.