Noroviruses constitute a major genus in the family Caliciviridae, which contains icosahedral viruses with positive-sense single-stranded RNA genome. From what I could find, it does not appear similar to coronaviruses – so using ivermectin may not work.
When it comes to treatments for norovirus, the need may not be as urgent, since most people recover from the symptoms in 48 to 72 hours—so antiviral development isn’t as robust.
Doctors advise people to drink plenty of liquids, since vomiting and diarrhea and lead to dehydration. In some cases, they may recommend anti-nausea medications to ease symptoms.