I made this the other night for dinner {using brown rice} and it was really good! You could easily subb ground turkey or chicken for the beef if beef isn't your thang.
I had a problem with too much liquid, I should of boiled it down so there wasn't any, or poured it out before putting it on the rice mixture, it diluted the creamy texture and taste a bit. So my suggestion for anyone making this, make sure there isn't alot of liquid in the beef mixture before laying it on the rice. I also cooked the rice earlier in the day, so I reheated it before mixing it with the milk and sour cream, I then put it in the oven to heat up a bit before laying the beef/cheese on top, about 10 minutes.
BTW.......for those wondering, when it says: Preheat oven to 375&176;. I think that is to mean 375 degrees and who ever typed this up was trying to do the degree sign. 
* Exported from MasterCook *
Cheesy Beef-and-Rice Casserole
Recipe By :
Serving Size : 0 Preparation Time :0:00
Categories :
Amount Measure Ingredient -- Preparation Method
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INGREDIENTS:
1/2 pound ground round
1 cup chopped onion
1 cup chopped green bell pepper
1/4 cup water
1 tablespoon chili powder
2 teaspoons ground cumin
1 1/2 teaspoons sugar
1/2 teaspoon dried oregano
1 can diced tomatoes -- (14.5-ounce)
undrained
1 can chopped green chiles -- (4.5-ounce) drained
3 cups cooked long-grain rice
1 cup fat-free sour cream
1/2 cup sliced green onions
1/4 cup skim milk
3/4 cup reduced-fat sharp cheddar cheese -- (3 ounces)
INSTRUCTIONS:
Prep Time: 30 minutes
Cooking Time: 30 minutes
Preheat oven to 375&176;.
Cook first 3 ingredients in a large nonstick skillet over medium-high heat until meat is browned, stirring to crumble. Add water and next 6 ingredients (water through chiles); bring to a boil. Cover, reduce heat, and simmer 10 minutes. Uncover and simmer an additional 2 minutes. Remove from heat; set aside.
Combine the rice, sour cream, sliced green onions, and milk in a bowl. Spoon rice mixture into a 9-inch baking dish. Top with beef mixture; sprinkle with cheese. Bake at 375&176; for 10 minutes or until thoroughly heated. Let stand 5 minutes before serving.
{mine was in a total of 15 minutes and plenty hot}
YIELD:
4 servings (serving size: 1-1/4 cups)
Description:
"Cooking Light"