So-called "Mexican food," as found in New Mexico, is not Mexican, it is a combination of food from Mexico with strong influences from Native American cuisine, along with other traits.
Furthermore, it is not a single form of cooking. For example, the food found in southern New Mexico is rather different from that found in the nothern part of the state. There is an historic reason for this: Early settlers, from both Spain and Mexico mainly went to the north; the southern part of the state was settled later, and there there was a wider racial makeup of the population; Anglos, for example, were more prevalent in the south than in the north, and they had a strong influence on cooking styles.
In addition, cooking styles, even in the north, vary widely, depending even on the village or town in which it is found, and, thus, the food in Mexican restaurants in New Mexico varies widely in style.