I don't think so. Socialism is the idea that the means of production should be controlled and regulated by the community. Now in today's world, every country's means of production, distribution, and exchange is either controlled by the Private Sector(Corporations, Banks) or Government(which is communist instead). I don't think there are any examples of a country that has all of its production and distribution controlled by the workers directly. Many of it is either controlled by a large Government or large Corporations.
So, can any nation ever be considered truly socialist?
No, not today. But I could be wrong. If anyone can give me am example of a nation where the means of production, distribution, and exchange is control by the workers or community as a whole, I'm all ears.