Add the chicken thighs, season with salt, pepper, and Italian seasoning. Sear for 3 minutes both sides. Remove the chicken from the pan and place into the greased 9x13 dish.
In the same skillet, add the spinach and sun-dried tomatoes and sauté until the spinach is wilted. Pour the mixture over the chicken thighs, scraping the pan.
Next, add the cooked gnocchi to the chicken dish. Make sure they are not stuck together. Place the skillet back over medium-high heat and melt the other two tablespoons of butter.