The phrase "nice big batch" is an idiomatic expression that means a large quantity or amount of something. It can be used to describe a group, collection, or supply that is substantial in size and quality. The term "batch" refers to a single portion or unit, while the adjective "nice" implies that it is pleasing, desirable, or satisfactory. Therefore, when put together, the phrase conveys an image of something generous, impressive, and enjoyable.