I think the problem is you do not eat enough sour cream. But yes, it does last longer if your issue is mold growing on your sour cream. Since it is sealed and there should be no air. But if the sour cream itself is going bad this likely will not help.
Why limit yourself to only tacos? Spoon a dollop of sour cream on your chilli or any hearty soup or stew, Mix it into gratin or mac'n'cheese before baking, make a salad with fresh cucumber and tomatoes, dill and/or spring onions... The world is your pot of sour cream