For sure, though it depends on which URL you mean.
For the
https://bsky.app/profile/aoc.bsky.so.../3ldhirk3zcc2c browser URL, could use that but something would have to reach out to Bluesky to get the URL that the iframe code would want (i.e.
https://embed.bsky.app/embed/did:plc.../3ldhirk3zcc2c). That would either have to be Javascript that would run in the browser after the page loads, or it would have to be a server side component that would have to be coded as a plugin into the forum software (and forum software would probably need to have some database code as well otherwise every page view it'd request the same iframe component code over and over and I assume they rate limit things at some point).
If someone already had the
https://embed.bsky.app/embed/did:plc.../3ldhirk3zcc2c URL then yeah the BBCode to embed that is simple.. I could put that in right now though it would be too hard to use for most people. Hence the idea that someone could take the normal URL
https://bsky.app/profile/aoc.bsky.so.../3ldhirk3zcc2c and paste it into a page and it would spit out the
https://embed.bsky.app/embed/did:plc.../3ldhirk3zcc2c URL which could then be used in a BBCode.
Or could put that kind of functionality into the forum but again that would involve adding to the forum software code.