Can you actually find nazis on Tiktok? I believe they have a pretty clear policy against hate in general which they apply just as liberally as for example facebook and youtube does.
TikTok's policy enforcement is pretty unreliable - sometimes it's very overzealous and sometimes it leaves bafflingly obvious stuff up. Folks on TikTok are pretty good at gaming it, there's lots of substitute words used and so on.
You won't see people saying "I love Hitler" or something, but you will hear Nazi ideology rephrased.