Preheat oven to 325°F (165°C). Coat a 9x13-inch baking dish with nonstick cooking spray.

Cook pancetta in a medium skillet over medium-high heat until lightly browned and crisp, about 5 minutes. Set aside.

Boil spaghetti in lightly salted water for 5 minutes. Drain pasta and reserve 2 cups pasta water.

Add egg yolks to a large mixing bowl and whisk until smooth.

Gradually pour 1 1/2 cups hot pasta water over egg yolks, whisking vigorously to prevent scrambling.

Whisk in Parmesan cheese, then heavy cream to form the sauce.

Combine cooked pasta, pancetta, and chicken with the sauce, toss to coat evenly. Transfer to prepared baking dish.

Bake in the preheated oven until hot and sauce thickens, stirring halfway through, about 20 minutes.

Remove from oven and let stand for 2-3 minutes to allow the sauce to continue thickening.