Based on that top tube decal, my guess would be that this is an early Nuovo Sport from around 1977-1979 (probably 1978, as the component codes suggest). I think Univega changed the font of the decals around 1980 (others on here may know for sure).
There are two undated catalogs
here, but they are both pre-1980. Although the scans are not very detailed, Viva Sport looks like it had chromed fork whereas Nuovo Sport didn't. The one thing I can see in your pictures that's different is that the rear derailleur on Nuovo Sport was a Suntour VGT Luxe, while the one on your bike looks like a Shimano Eagle.
These are the only decent pictures of an early Nuovo Sport (1978 in this case) that I could find.