Season both sides of each chicken breast with Italian seasoning, salt, and pepper.

Heat olive oil in a large skillet over medium heat. Add the chicken and sear for 3-4 minutes on each side, until golden. Remove the chicken from the skillet and set aside.

In the same skillet, add the onion and sauté for 2-3 minutes until softened. Add the garlic and sun-dried tomatoes and sauté for another minute until fragrant.

Add the spinach to the skillet and sauté until just starting to wilt. Stir in the heavy cream and Parmesan cheese, and bring to a simmer.

Return the chicken to the skillet, cover, and simmer until the chicken is cooked through, about 5 minutes. Garnish with fresh basil when serving.