Season chicken with salt, pepper, and garlic powder. Sear in olive oil over medium-high heat 4–5 minutes per side until browned and cooked through; transfer to a plate.
Reduce heat to medium, add butter and garlic; sauté 30–45 seconds until fragrant.
Stir in sun-dried tomatoes, chicken broth, and heavy cream; simmer 2–3 minutes.
Add Parmesan and Italian seasoning, stir until sauce thickens slightly.
Fold in spinach until wilted, return chicken to pan and spoon sauce over top for 1–2 minutes to heat through.
Sprinkle parsley and serve with pasta, rice, or crusty bread.