Nogo Vodka is a brand of alcohol in the HD Universe.
It is most likely sold in the Superstar Café (as that's where it's advertised). In GTA IV, bottles of Nogo can also be found on tables in the Triangle Club and Bahamas Mamas, and there's a bottle near the radio in the Broker Safehouse.
In GTA V, it is mostly found in 24/7, Limited Service and Rob's Liquor stores in San Andreas.
In the iFruit App, an alcoholic drink similar to Nogo can be fed to Chop, however, it will make him throw up and decrease his happiness, so it's best not to feed him this.
A bottle of Nogo Vodka in GTA IV.
Bottles of Nogo Vodka in GTA V.