Comfort food chicken and rice casserole

I picked up a couple of very useful 15 inch square aluminum pans last year. These make a pretty big casserole but will still fit in a standard oven. I like to make casseroles and cut them into portions and use those freezer ziplock bags to freeze them.
I also have bought a rice cooker, which is turning out to be very useful. I spent many years making rice in an ordinary pan and it was fine, but a rice cooker lets me put the rice and water in the cooker and then go do something else, and come back to perfect rice that is kept warm after it cooks.

6 cups raw arborio rice, cooked (will make around 12 cups of rice)
1 medium onion
3 jalapeños
4 cups cooked cubed chicken
2 cups chicken broth, homemade or canned
1 lb cheddar/monterrey jack cheese, shredded or grated
3 lbs sour cream
salt
oil 3 tbs

Chop onion and jalapeno and fry until onion is transparent


Oil your 15 inch pan and set aside

preheat oven to 350

In a very large bowl, combine cooked rice and 2.5 lbs of sour cream. Pour in the chicken broth. Salt to taste. Add cubed chicken and the onion/jalapenos and stir well, and put in the aluminum pan. Top with grated cheese and cook 30 minutes at 350.
Remove from oven, allow to cool slightly and cut into serving size portions. Serve with a spoonful of sour cream on top.