Chicken, Broccoli, and Rice Casserole

1/2 cup uncooked rice
1 cup water
1/2 white onion
1 tbsp olive oil
1 1/2 cups shredded chicken (I used a rotisserie chicken)
salt and pepper, to taste
3/4 cup milk
1 1/2 tbsp flour
6 oz frozen broccoli
1/2 cup shredded swiss cheese
1 tbsp Italian breadcrumbs
hot sauce for garnish

Pour the rice and water in a small saucepan. Bring to a boil, then reduce heat to low and simmer for 15 minutes, or until the water has been absorbed. Fluff rice with a fork and set aside.
While the rice is cooking, chop the onion. In a large oven-safe skillet, add the olive oil and heat over medium heat, then add in the onion and cook for 3-4 minutes, or until the onions are just starting to get tender.
Add the chicken into the skillet and season with salt and pepper to taste. Continue cooking for another 3-4 minutes.
While the chicken and onions are cooking, whisk together the milk and flour in a small bowl.
Pour the milk mixture into the chicken and onions and cook for 3 minutes, or until the mixture starts to thicken and bubble.
Microwave the broccoli for 2 minutes, or until no longer frozen. Add the rice and broccoli into the chicken, and mix well.
Mix 1/4 cup cheese into the mixture, and top with the remaining 1/4 cup cheese.
Sprinkle the breadcrumbs over the cheese.
Place the pan in the oven and broil for 1-2 minutes, or until the cheese has melted and the breadcrumbs are toasted.
Drizzle with hot sauce if desired.