So far all of the knockoff Vivi's I have seen were made by Smoktech and the best way to distinguish the difference was by looking at the heads.
In this picture the one on the left with the flat top is the Vision brand and the one on the right with the pointy top is the
smok brand.
View attachment 213165
Also ALL of the real Mini Vivi Nova's I have seen say "Vivi Nova" on the tank, not "Mini Nova". Although I guess it is possible that they changed the wording a bit in recent production runs.
Knockoffs can and will copy the packaging as well as the design so sometimes it can be really difficult to spot knockoffs.
Edit: Once more thing. The Real Vivi heads have 3 different wick configs based on the resistance of the replacement head that you get. The 2.8 Ohm has 1 thick wick on each side, the 2.4 Ohm has 4 really thin wicks on each side, and I THINK the 1.8 Ohm has 2 wicks on each side. I might be off on which is which since I am doing this from memory.