Preheat the oven to 375°F (190°C).

In a mixing bowl, combine the chopped spinach, drained artichoke hearts, cream cheese, Parmesan cheese, garlic powder, onion powder, salt, and pepper. Stir until well combined.

Place the chicken breasts between two pieces of plastic wrap. Use a meat mallet or rolling pin to pound them to an even thickness of about 1/2 inch.

Carefully slice a pocket in each chicken breast, ensuring not to cut all the way through.

Stuff each chicken breast with the spinach-artichoke mixture, packing it in tightly, and secure with toothpicks if necessary.

Heat olive oil in an oven-safe skillet over medium-high heat. Sear each stuffed chicken breast for 4-5 minutes on each side until golden brown.

Transfer the skillet to the preheated oven and bake for 20-25 minutes or until the internal temperature reaches 165°F (74°C).

Remove from the oven, let rest for 5 minutes, then remove toothpicks if used, and slice the chicken to serve.