Preheat the oven to 375°F (190°C) and prepare your workspace.

Place chicken breasts between plastic wrap and pound to about 1/2 inch thick.

In a bowl, combine spinach, sun-dried tomatoes, feta cheese, and pine nuts; spread mixture evenly over each chicken breast.

Roll each chicken breast tightly and secure with toothpicks or kitchen twine.

Heat olive oil in an oven-safe skillet over medium heat and sear each roll until golden brown (3–4 minutes per side).

Transfer the skillet to the oven and bake for 25–30 minutes or until internal temperature reaches 165°F (75°C).

Let rest for 5 minutes before slicing and serving with balsamic sauce.