Convincing other developers to use nullptr over NULL

Not sure whether this is more appropriate for r/cpp, but I thought I'd ask here first.

I always use nullptr over NULL, for the reason that overload resolution with NULL can lead to surprising outcomes because it's an integer, and not a pointer. (also it's shiny and "modern", or it can be considered more idiomatic C++, I guess)

So I'm working with a new team member who is not convinced. He thinks this reason is really obscure and that you will rarely, if ever, encounter a real life scenario where that reason comes into play. I couldn't come up with an organic scenario that could happen in real code, and to be honest - I don't think I've seen something like that in the wild.

Would you insist on strictly using nullptr in your codebase? I keep seeing him use NULL in his pull requests and I'm starting to wonder if I should stop being the "code police" and give up on this battle.