Prep the zucchini noodles: Spiralize the zucchini and spread the noodles on a clean kitchen towel.
Sprinkle lightly with salt and let them sit 10 minutes to draw out moisture. Pat dry to reduce excess water.
Season the chicken: Toss the chicken with 1 tablespoon olive oil, Italian seasoning, a generous pinch of salt, and black pepper.
Sear the chicken: Heat a large skillet over medium-high. Add the remaining 1 tablespoon olive oil.
Cook the chicken in a single layer, 3–4 minutes per side, until golden and cooked through. Transfer to a plate and tent loosely with foil.
Start the Alfredo base: Reduce heat to medium. In the same skillet, add butter.
When melted, add garlic and cook 30–45 seconds until fragrant (don’t brown it).
Build the sauce: Pour in heavy cream and bring to a gentle simmer. Stir in nutmeg if using. Let it bubble softly for 2–3 minutes to thicken slightly.
Add the Parmesan: Lower the heat.
Stir in Parmesan a handful at a time until melted and smooth. Season with salt, black pepper, and a pinch of red pepper flakes if you like heat. If the sauce gets too thick, loosen with a splash of cream or a little water.
Toss in the chicken: Return the chicken (and any juices) to the skillet.
Stir to coat with sauce.
Cook the zoodles gently: Add the zucchini noodles to the pan and toss for 1–2 minutes, just until warmed and slightly tender. Do not overcook or they’ll release too much liquid and get soggy.
Finish and serve: Taste and adjust seasoning. Add a whisper of lemon zest or a squeeze of lemon if you want a bright pop. Garnish with parsley and extra Parmesan.
Serve immediately.