Both are correct. The second one could use "it's" instead of "it has". In America, we can also say "it has to be expensive" (without "got").

Both are correct

Both are correct although the 2nd sentence is used more casusally and it's more informal.

This jacket looks nice. It must be expensive. This jacket looks nice. It has got to be expensive. Note the spaces I created after the full stops. They are important when writing. Also, first pair of statements uses the imperative 'must'; so it's called an impertive statement. In the second pair, the second part is actually a question, (albeit, probably rhetorical) so it needs a question mark. This jacket looks nice. It must be expensive. (2 statements) This jacket looks nice. It has got to be expensive..? (1 statement; 1 question.) Some people use these two experessions interchangeably, in casual speech, and do not mean ot to be a question at all. Those people are reducing their own scope for communication. It's the reduction, some might say, evolution of modern English through texting laziness. I do it too. It's a sad truth of the modern age: Dwindling numbers of would-be communicators have the time or inclination to explain themselves adequately to suit their audience. Fewer still can be bothered finding out or exploring the beauty of expression available to us who just happen to be the most expressive species known ever to have existed in the history of the Universe. Ah well, back to reality tv on Youtube and the footy. Welcome ot the school of deeper thinking.