CHICKEN AND RICE CASSEROLE!! Best Recipe Ever!

2 cups white rice
1 white onion (diced)
2 TBSP AP flour
3TBSP butter
5 cups chicken broth
1 cup heavy cream
1 tsp salt
1/2 tsp black pepper
5-6 chicken thighs
2 tsp Italian seasoning
1/2 tsp garlic powder
1/2 tsp paprika