Nutrition is the process by which our bodies take food and transform it into energy. Nutrients are substances that provide nourishment. These two words are related but they are not interchangeable.
From Cambridge dictionary
(1) the substances that you take into your body as food and the way that they influence your health:
Good nutrition is essential if patients are to make a quick recovery.
(2) the process of taking in and using food, or the scientific study of this: She's a professor of nutrition at Columbia University.
(1) any substance that plants or animals need in order to live and grow:
It's good soil - full of nutrients.
A healthy diet should provide all your essential nutrients.