Nopal Cactus are what we call Opuntia. There are hundreds of different opuntia. The one that is most edible is called Opuntia ficus-indica. It is a rapid grower, has large green pads, and as the pads (cladodes) grow older the spines appear (glochids first). This cactus has long been used as food in Mexico and the culinary popularity of it is expanding. There are studies on the nutrient value, healthful benefits of it, and the economic value. Many recipes abound for the jams and jellies (from the large bountiful fruit aka Tuna) and salads and "green bean" type dishes (especially from the more tender green pads). [Look up Nopal Cactus on Wikipedia. There's quite a list of Mexican dishes using Nopal.]
Opuntia ficus-indica is easy to grow in the right conditions. It is hardy in zones 8b to 10 but can elsewhere live in microclimates, especially if the drainage is good and there is sufficient protection against temperatures much below 30 degrees F. Damage may occur at that temperature, but if the base or core of the plant is not damaged, new growth may appear when warmer weather returns. As with any desert landscape, plant placement is important. Walls can offer protection and can also produce a great deal of reflected heat depending on other nearby shade giving structures and plant material. This cactus is somewhat typical of most in that it will tolerate quite a bit of water in the landscape as long as there is adequate drainage. Nitrogen fertilizer can encourage increased growth of the green pads. Higher phosphorus and potassium fertilizer encourages flowers and fruits. The plant is most easily propagated by rooting cuttings. (Cuttings should be taken right at the point of attachment to the pad directly beneath.)
The most common application of Opuntia ficus-indica in the Southern Nevada area is purely landscaping. Because it can quickly grow quite large, it is sometimes used as a "barrier" plant along otherwise exposed property lines. It not only blocks the view, but also deters intruders be they human or other animal forms.