There are various synonyms for the phrase "hornets' nest" which refer to a situation that is likely to cause trouble or conflict. Some of these synonyms include a "can of worms," "Pandora's box," or "firestorm waiting to happen." These phrases signify that opening a can of worms or Pandora's box will lead to a chaotic situation, while a firestorm waiting to happen implies that a big battle will occur soon. Another synonym is "powder keg," suggesting a situation that is explosive and that can easily and quickly escalate. In summary, while "hornets' nest" is a common phrase, there are numerous alternatives that suggest a problematic scenario that requires caution.