01 - Preheat oven to 400°F. Lightly grease a baking dish with cooking spray or olive oil.
02 - Heat a skillet over medium heat. Add spinach and cook for 2-3 minutes until wilted. Remove from heat and let cool slightly.
03 - Combine cooked spinach, feta cheese, cream cheese, garlic, dill, nutmeg, and black pepper in a mixing bowl. Mix until thoroughly blended.
04 - Pat chicken breasts dry with paper towels. Using a sharp knife, carefully cut a horizontal pocket into the side of each breast, taking care not to cut completely through.
05 - Divide spinach-feta mixture evenly among chicken breasts. Stuff each pocket and secure with toothpicks if necessary.
06 - Brush exterior of chicken breasts with olive oil. Season evenly with salt, black pepper, and paprika.
07 - Arrange stuffed chicken in prepared baking dish. Bake for 25-30 minutes until internal temperature reaches 165°F and juices run clear.
08 - Remove toothpicks. Let chicken rest for 5 minutes before serving. Garnish with lemon wedges and fresh parsley if desired.