Season the chicken breasts with salt and pepper. Heat the olive oil in a large skillet over medium-high heat and sear the chicken 5–6 minutes per side, until golden and cooked through. Set aside.
In the same skillet, sauté the garlic 30 seconds. Pour in the heavy cream and chicken broth; whisk in the parmesan and Italian seasoning. Simmer 3 minutes until slightly thickened.
Stir in the sun-dried tomatoes and spinach; cook 2 minutes, until the spinach wilts.
Return the chicken to the skillet and simmer 5 minutes, spooning sauce over the top. Serve hot.