In New Mexico there is no duty to retreat when there is a threat of attack. Deadly force may be used to protect one's self or another in the face of immediate threat of a felony, serious injury, or death. When deadly force is used it must be used in a way that a reasonable person would have.
Castle Laws are laws that address the use of force when defending one's self inside their home, or on their property. Some states expand this to vehicles, and the person's place of work. Castle Laws generally include: the places where this law applies, the requirements fro use of deadly force, if there is a duty to retreat, the amount of force that maybe used in defending one's self or others. These vary widely from state to state.