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 mince the garlic clove.
In a medium skillet over medium heat, cook the pancetta until the fat renders and it becomes crispy.
Add the diced chicken to the skillet with the pancetta and sauté until cooked through and lightly golden.
Add the minced garlic to the skillet and cook for 30 seconds until fragrant, then turn the heat to low.
In a small bowl, whisk together the whole egg, egg whites, grated parmesan cheese, and black pepper until well combined.
Reserve 0.25 cup of the starchy pasta water, then drain the spaghetti.
Add the hot pasta to the skillet with the chicken and pancetta, tossing to combine.
Remove the skillet from the heat entirely and quickly pour in the egg mixture, tossing constantly to create a creamy sauce without scrambling the eggs.
Thin the sauce with the reserved pasta water as needed until it reaches a silky consistency and serve immediately.