Are superworms and mealworms the same?

No, although they are related since they are both darkling beetle larvae. Superworms are Zophobas morio, and mealworms are Tenebrio molitor.
Superworms are much larger than mealworms (giant mealworms being an exception. They also have a dark brown head and tail, while mealworms tend to be lighter, with little patterning. Because they are larger, superworms have a higher meat-to-shell ratio compared to mealworms, which means that they contain less chitin per insect.