1. Heat oven to 375 degrees. Prepare cooking dish by greasing, spraying or lining with parchment paper. Butterfly chicken breasts.
2. In medium bowl, mix cheese, nutmeg and spinach until blended. Spread 1/4 of mixture within fold of butterflied chicken. Place chicken in dish. Sprinkle with salt and pepper. Drizzle with butter.
3. Bake uncovered 45-55 minutes or until well done.