Preheat oven to 375° F.
Add 1-2 teaspoons oil in a large skillet over medium heat. Add the spinach and garlic and cook until wilted, 3-4 minutes. Let cool.
Set the spinach/garlic and sundried tomatoes aside. Combine remaining filling ingredients, then gently stir in the spinach/garlic and tomatoes. Set aside.
Pat the chicken dry. Use a sharp paring knife to create a pocket for the stuffing. (Slice the side of the chicken that has the fold on the bottom.) Be careful not to cut all the way through to the other side.
Stuff each chicken breast with the filling. Sprinkle the top of the chicken with salt, pepper, and paprika.
Heat oil in a large skillet over medium-high heat. Once the oil is glistening and hot, add 2 chicken breasts at a time and sear each side until it begins to turn golden, 2-3 minutes.
If your skillet is not oven safe, transfer the chicken to a baking dish.
Bake uncovered at 375° for 17-20 minutes, or until the thickest part of the chicken reaches 165°. Rest for 5 minutes prior to serving.
