Preheat your oven to 375°F (190°C). In a mixing bowl, combine spinach, sundried tomatoes, mozzarella, and cream cheese. Add garlic powder, Italian seasoning, salt, and pepper. Mix until well combined.

Take chicken breasts and slice a pocket into each, being careful not to cut all the way through.

Stuff each chicken pocket with the mixture, packing it well. Secure with toothpicks if needed.

In a skillet, heat olive oil over medium-high heat. Sear each stuffed chicken for 3-4 minutes on each side until golden brown.

Transfer the skillet to the oven and bake for 25-30 minutes until cooked through (165°F internal temperature).

Remove from oven, let rest for 5 minutes, then slice and serve.