To be honest, I have accessibility issues on the new Skype 8 on iOS.
I don't know why Microsoft chose to sacrifice accessibility when developing Skype 8.
But as of now I do not know whether Skype 8 is still in the preview stage for Windows; and whether it's even compatible with Windows 7.
If you're on Windows 10 you can use the built-in Skype app; NVDA works with it just fine; in fact I find the Windows 10 Skype app easier to navigate than the Skype desktop app.