Generally, "nevertheless" acts as a conjunctive adverb, which means it connects two independent clauses.
* If the two clauses are separated by a comma, you do not need a comma after "nevertheless."
* Example: "The weather was terrible, nevertheless, we had a great time."
* If the two clauses are not separated by a comma, you do need a comma after "nevertheless."
* Example: "The weather was terrible; nevertheless, we had a great time."
It's important to note:
* Sometimes, you might use "nevertheless" at the beginning of a sentence. In this case, you'll always need a comma after it.
* Example: "Nevertheless, we decided to go ahead with the trip."
So, the rule of thumb is to check if the clauses are already separated by a comma. If not, use a comma after "nevertheless."