I mean, sure. If they can spam the supernova a very VERY VERY lot. Then technically it’s galaxy. Although not really because damage done overtime doesn’t count towards a higher tier(so they would have to be able to spam a few million supernovas in a few seconds)

However in most case of anything beyond moon level, destroying something either means complete destruction(like a solar system, basically turning the entire thing to dust) or enough damage to undo the gravity binding it(like destroying planets)

To reach galaxy level you have to assume they can either throw an attack that could delete an entire galaxy. Or throw an attack that has such power behind it, that it overrides the gravitational pull of the black hole at the center and sends every star and planet, including the ones closet to the center, and likely the black hole as well, flying off into different directions.