Technically speaking, pistol stabilizing braces are legal in NY. However, there are some restrictions on how they can be used. For example, you cannot use a stabilizing brace to turn a pistol into a short-barreled rifle. Doing so would violate state law and could result in some pretty serious penalties.
It’s also worth noting that just because something is technically legal doesn’t mean it’s a good idea. There have been several instances where people have used pistol-stabilizing braces in a way that allowed them to fire their weapon one-handed, which is very unsafe. So just be careful if you do choose to use one of these devices and make sure you understand all the rules and regulations surrounding their use.