Prep the chicken: Pat the chicken dry. Season both sides with salt, pepper, Italian seasoning, and garlic powder. If using large breasts, slice horizontally to make cutlets for quicker, even cooking.
Brown the chicken: Heat olive oil in a large skillet over medium-high.
Add chicken and sear 4–5 minutes per side until golden and just cooked through. Transfer to a plate and tent with foil.
Build the base: Lower heat to medium. Add butter to the same skillet.
Stir in garlic and sun-dried tomatoes; cook 30–45 seconds until fragrant. Do not let the garlic brown.
Deglaze: Pour in chicken broth and scrape up browned bits from the pan. Simmer 2–3 minutes to reduce slightly.
Make it creamy: Stir in heavy cream.
Bring to a gentle simmer, then add Parmesan and red pepper flakes. Whisk until the cheese melts and the sauce thickens slightly, 3–4 minutes. Season with a pinch of salt to taste.
Add greens: Stir in spinach and let it wilt, about 1 minute.
If the sauce gets too thick, splash in a bit more broth or cream.
Return the chicken: Nestle chicken back into the skillet along with any juices. Simmer 2 minutes to warm through. Finish with lemon juice for brightness, if using.
Serve: Garnish with fresh basil.
Spoon sauce over the chicken and serve hot with your favorite low-carb sides.