The animated film “The Nut Job” and its new sequel, like many a movie before them with the theme of man vs. nature, depicts a world in which grotesque humans are ultimately rendered powerless by animals (in this case, those of the cute, talking, saucer-eyed variety). Unfortunately, despite its adorable heroes, you’d have to be nutty to sit through “The Nut Job 2: Nutty by Nature,” a largely unengaging modern-day animal fable. The saga picks up some time after the first film left off, with Surly the purple squirrel (voice of Will Arnett) and his friends having become complacent after gaining free rein over an abandoned nut shop and its seemingly unlimited supply of food.