Today, not even close. The party has neo-nazi roots, but the vast majority of the “old-guard” are long gone (afaik), most of them ending up in AFS (swedish equivalent of AFD) or Nordfront (actual nazis). If someone behaves questionably, they tend to be thrown out head-first rather promptly.
The SD gained popularity and won their platform by a) becoming more moderate and b) being the only mainstream-ish party to speak out against the mass immigration waves of the 2010s, something which they at the time were entirely shunned for. Today however, almost all politicians agree that the open door policy for refugees and economic migrants went too far.
Many of our problems here in Sweden today have to some degree been caused or exacerbated by that careless era (not that there weren’t problems before). Seeing welfare systems be dismantled, schools closing, worsening healthcare, infrastructure etc. etc. whilst at the same time huge amounts of resources were diverted to immigrants pushes folks in that direction. It also really doesn’t help that many kinds of violent crime previously entirely unheard of have become commonplace in less than adecade.
They said things would go to shit, things went to shit, now more than a fifth of Swedish voters voted for them in the last election, making them the 2nd largest party.
All in all it’s not that surprising that bringing folks from one cultural extreme into a society at the opposite cultural extreme ends up causing tensions and issues…