Cook and stir the meat in a large skillet until the meat is brown. Drain off the excess fat. Stir in the soup mix, oats and water. Cover and simmer for about 5 minutes, stirring occasionally. Stir in the sour cream and eggs. Spread the mixture evenly in the skillet then sprinkle the cheese over the top. Cover and simmer until set, about 5 minutes. Serve with catsup, if desired.