Anything goes, it’s a permissionless protocol

There are no rules. A client, relay, or image host may have them, but Nostr as a whole does not. You can move to another client or another relay or another image host if you need to and all of your followers and notes just show up. For example, if you're on Damas, go check out Primal (TestFlight), or Plebstr, or NOS social, all of your notes and contacts will be there even though you're using a new app. It's because they all use the same protocol. Kind of like email.

#nostr is the place where nudity is aloud. This place is built for us . We don’t need to censor ourselves here bb. We don’t get banned nor deleted. Others may not like us being open and comfortable with our body, but that’s on them not us. 🤷🏻‍♀️

Some clients support a content warnings where you can mark posts as NSFW for example. Content is then blurred for users before accepting the warning. More and more apps support this.