Preheat oven to 375°F.
Cut chicken into small, even pieces.
Season chicken with salt and pepper.
Heat olive oil in large pan.
Cook chicken until golden brown.
Remove chicken from heat completely.
Squeeze excess water from thawed spinach.
Mix cream cheese until smooth.
Add heavy cream to cheese mixture.
Stir in garlic and Italian seasoning.
Combine spinach with creamy mixture.
Add cooked chicken to mixture.
Pour everything into greased baking dish.
Top with mozzarella and parmesan cheese.
Cover with foil, bake 25 minutes.
Remove foil, bake 10 more minutes.
Let rest 5 minutes before serving.