Season both sides of the chicken breasts with salt and black pepper.
Heat olive oil in a large skillet over medium-high heat.
Add the chicken breasts to the skillet and cook for 5-6 minutes on each side until golden brown and cooked through. Remove the chicken from the skillet and set aside.
Reduce heat to medium and add the minced garlic to the same skillet. Sauté for 1 minute until fragrant.
Add the chopped sun-dried tomatoes and cook for 2 minutes, stirring frequently.
Pour in the heavy cream and chicken broth, stirring to combine.
Add the grated Parmesan cheese, Italian seasoning, and crushed red pepper flakes. Stir until the cheese is melted and the sauce is smooth.
Add the fresh spinach to the skillet and cook for 2-3 minutes until wilted.
Return the cooked chicken breasts to the skillet, spooning some sauce over the top.
Simmer for 2-3 minutes to allow the flavors to meld and the chicken to reheat.
Serve the creamy Tuscan chicken hot, spooning extra sauce over the top.