Prep the zoodles: Spiralize the zucchini using a spiralizer. Place in a colander and sprinkle with a pinch of salt.
Let them sit 10 minutes to release excess moisture, then gently pat dry.
Season the chicken: Pat the chicken dry. Season both sides with 1/2 teaspoon salt and 1/4 teaspoon pepper.
Sear the chicken: Heat olive oil in a large skillet over medium-high. Add chicken and cook 3–4 minutes per side, until golden and cooked through.
Transfer to a plate and tent with foil. Slice into strips.
Build the sauce base: Reduce heat to medium. Add butter to the same skillet.
Stir in garlic and cook 30 seconds, just until fragrant—don’t brown it.
Deglaze: Pour in the chicken broth, scraping up browned bits. Simmer 2–3 minutes to reduce slightly.
Creamy finish: Lower heat to medium-low. Stir in half-and-half (or coconut milk).
Sprinkle in Parmesan gradually, whisking until smooth. Add lemon zest, a squeeze of lemon juice, and red pepper flakes if using. Taste and season with salt and pepper.
Add the chicken: Return sliced chicken and any juices to the pan.
Simmer 1 minute to warm through.
Toss with zoodles: Add zoodles to the skillet. Toss gently for 1–2 minutes, just until lightly warmed and coated. Do not overcook or they’ll get watery.
Finish and serve: Top with parsley and a little extra Parmesan. Serve immediately while the zoodles are tender-crisp.