No. Beautiful is krásné. It is nicer than nice or pretty.

You're right that "hezký" usually means "pretty" and that's why "pretty car" is accepted. However, note that there's a difference between "hezký/krásný" as there is between "pretty/beautiful". As to the "official" translation - if you comment on someone's car saying "hezké auto", it'd generally be best translated as "nice car".

mmm for that, I would use "dobré auto" (and it would work ironically too same as in english)