There’s no evidence there was a Nazi parliamentary groups committing mass murder. Which is why the UN court ordered Russia to halt its invasion and did not accept genocide claims against Ukraine when Russia used that narrative as a pretext.

The war in Donbas began in 2014, long before the 2022 invasion, and by 31 December 2021 about 14,200 to 14,400 people had been killed, including at least 3,404 civilians; most civilian harm came in 2014 to 2015 and fell sharply after the Minsk ceasefire periods.

Some Ukrainian volunteer units with far right members existed, most notably Azov and Aidar; credible groups documented serious abuses by certain fighters from these units in 2014, and they urged Kyiv to investigate and bring them under firm command. Those findings support claims of abuses, not a claim of large scale Nazi formations carrying out mass murder

Kyiv moved to integrate volunteer battalions into formal structures and to prosecute rogues such as the Tornado unit; this shows problems were real, and also shows state action against them rather than official sponsorship of systematic killing of civilians.