Is something skipped in this sentence? Probably between "than" and "is"?
No, there is nothing skipped in this sentence. "Than is" is an expression used for comparison, and it is usually placed between adverbs and adjectives like "more" or "less" and another adjective. In the case of the video here, the expression "more than is justified" is used to show that the amount of money printed is more money than they have reason to print. Here's some examples of the expression "than is" in other contexts: Ex: She cooked less food than is enough for five people to eat. Ex: He bought more clothes than is needed for a year.