Cook box of rice according to packaged directions.
In skillet, melt butter and sautee onion and celery over medium heat until softened, about 5 minutes.
Once cooked, add rice and cooked onion and celery into large bowl. Add cream of chicken soup, diced chicken, vegetables, cream and salt and pepper. Mix well. Spread into a lightly greased casserole dish. (9x9 glass dish is fine too.)
Top with cheese. Cover with foil and warm thoroughly at 350 degrees for at least 20 minutes (and up to 60). Serve warm with a side salad.
Notes
*I use cream of chicken condensed soup but a cream of mushroom of cream of celery soup would work too. As long as you like the flavor of the soup you're using, it should work just fine.