In Soylent Green (1973), a cop says to another one (wounded, dying): "I promise, Tiger. I promise." I think this word was used only once in the film. What's the origin of using this address? I guess it's from (American) mass culture of pre-1973, like another movie or book or comics, but what? Or am I wrong and this film IS the origin? :-)
"Tiger", as a nickname, dates back to the 1700's. It is generally used as a form of respect or love, as we all know that tigers are dangerous and courageous animals.
Tony the Tiger, the famous mascot for Kellogg's Frosted Flakes, was first introduced in 1951.
Given these two facts, it seems highly unlikely that the origin was a 1973 movie. I'm not sure that anyone can give a definitive answer to an exact movie where that nickname is first given, as it's not something that would be easy to research.