I've also read that it's not a good idea to put the channel forms tag inside the channel entries tag, but I'm doing it anyway for a site where I couldn't find another solution to the problem I was encountering and it's working.
So I would say (like Romans-8---31-39 said in the comment) try it as a separate tag if possible. If you can't try nesting it and see if it works for your site. If that doesn't work you could have the channel form in an embed.
Ideas about why it's not a good idea: I would guess because you're doubling the query on the database for one thing, but it would also be doing that separating them or using an embed. The other thing is that in the parse order the surrounding channel entries tag gets processed before the channel form entry, and I'm not sure if that entry tags are being parsed by the channel entries tag or the channel forms tag.