Sprinkle chicken cutlets with 1/8 teaspoon each of salt and pepper.
Heat olive oil in a large skillet over medium-high heat. Add chicken and cook, turning once, until golden-brown and cooked through (6-8 minutes). Transfer to a plate.
Add spinach, red onion, roasted red peppers, and sun-dried tomatoes to the skillet. Sauté for 1 minute until spinach begins to wilt.
Turn the heat to high and pour in white wine, scraping up browned bits from the pan. Let the wine reduce almost completely, about 2 minutes.
Lower the heat to medium and stir in sour cream along with any juices from the resting chicken. Season with the remaining salt and pepper. Let the sauce simmer and thicken slightly, about 2 minutes.
Return the chicken to the skillet, turning to coat each piece in the sauce.
Serve warm, spooning the sauce generously over the chicken. Enjoy!