Wash and chop the spinach leaves. Grate the parmesan cheese if needed into a bowl and set aside.
In a small bowl mix together the cream cheese, parmesan cheese, mayonnaise, spinach, and garlic, set it aside.
Slice a pocket in each chicken breast, making sure not to go all the way through the chicken breast.
Drizzle the oil over the chicken.
In a small bowl mix the paprika, salt, garlic, and onion powder togeather. Sprinkle the paprika, salt, garlic, and onion powder mixture on top of the chicken breast and rub the spice mixture over both sides of the chicken.
Take the spinach mixture and stuff it into the holes of the chicken breast.
Place the chicken in a baking dish. Bake for 25-30 minutes or until the chicken reaches 165°F.