LLM is the model itself, a direct interface to the language model (e.g., OpenAI, Anthropic). You can call it directly with a prompt and get a response.

LLMChain is a LangChain wrapper that combines the model (llm) with a PromptTemplate and optional output logic. It doesn’t replace the LLM; it uses it internally to build a reusable, parameterized pipeline.

So it’s not one over the other, you typically use them together:
the LLM provides the intelligence, and the LLMChain structures how prompts are created and managed when interacting with it.