Spiced Tea with Tang is a high-calorie beverage, so is not particularly healthy overall. The ingredients usually feature one part instant tea, one part Tang and one part sugar, with additional spices. Tang is a good source of vitamin C and calcium, but the additional sugar is not nutritious.
If counting calories or watching sugar intake is not a concern, there is nothing wrong with drinking spiced tea with Tang. However, an average serving size contains about 90 calories, most of which comes from the Tang powder and the added sugar. This is less than in a standard serving size of soda, but it is not a low calorie count for a hot beverage.