In a large mixing bowl, combine cooked rice, sour cream, shredded cheddar cheese, cream of mushroom soup, chopped onions, and chopped bell peppers. Mix well.
Season with salt and pepper to taste.
Transfer the mixture to a baking dish and spread evenly.
Bake in the preheated oven for 30 minutes, or until the top is golden and bubbly.
Let it cool for a few minutes before serving.
Notes:
Feel free to add cooked chicken or ground beef for a heartier meal.