I just wanted to share this with everyone, as this is a new development. Just earlier tonight, rdanbrook added dedicated turbo keys to NEStopia.
You can set the pulse rate, but just a heads up if you set it too fast some games won’t work with it. I found 4 is reliable.
This is now by far my favorite way to emulate NES. There’s still a handful of games that FCEU will run that NEStopia will not, but now both cores have basic turbo support, and I’m very happy about that. Try it out!