It is unlikely that Iran decided to not sink US carriers because of fear of nuclear retaliation. It is much more likely that before the air attack started, Iran

It is unlikely that Iran decided to not sink US carriers because of fear of nuclear retaliation. It is much more likely that before the air attack started, Iran's leadership preferred not to do anything that could make an attack more likely, such as attacking carriers. And after the invasion started, they would have loved to attack carriers but did not have the military capability to do so.