This one is not under 500 calories unless you eat a small amount, but the kids love it and it is quick and easy, which is what I look for, something that I can whip up after work and it doesn't take a long time, but tastes yummy!  Brown 2 pounds chopped boneless, skinless chicken breasts, season while browning with pepper, garlic powder and seasoned salt, melt 1 pound Velveeta in the microwave 1 min at a time, add a can of cream of chicken soup and 1 can Rotel tomatoes, mix with the browned chicken.  Either serve with tortilla chips (my favorite way) or mix with 1 pound cooked pasta (kids favorite way).