A person with very deep and forceful feelings is 'intense', there is not necessarily 'nervous' feelings involved. He could be passionate, energetic ,keen or eager.The description could have both positive and negative connotations. This person could be on the other hand stiff, lofty, full of affected dignity. 'tense' is similar in meaning with ' nervous'. It means strained, not relaxed or natural , not spontaneous ,restless and under pressure. 'nervous' means being very excitable and sensitive due to being worried or any external irritation. It is also being agitated or edgy. 'tense' and 'nervous' are close in meaning. Notice that 'nervous' and 'tense' are always negative states.

Intense (强烈) can mean forceful, demanding, overbearing. It's usually applied to situations. "John studied his entire textbook in one week, a very intense experience." But it also can be applied to people: "The fitness trainer kept yelling and yelling at her, his voice loud and intense." Tense (紧张) means someone is worried, fidgety, anxious, "on edge". Maybe he's doing something that requires a lot of concentration and he's worried about making a mistake. "Dan was very tense when he took the English test." It can also be used to talk about situations, meaning that something is about to change, "about to snap": "The two men pointed their guns at each other, waiting. The situation was very tense; gunfire could happen at any moment." A good way to think of it is "tense" can be used when talking about a string pulled very tightly, ready to break in half at any moment ("He tensed the string"); the emotional state is very similar. :) Nervous (生怕 or 伈) can sort of overlap with "tense", but it is more specific: it means to be worried about something, to be concerned or anxious with something. While "worried" can mean just a state of mind, "nervous" usually implies that someone actually appears anxious. "He was nervous taking the test; he was sweating and his hands were shaking."