Sub-adults and adults will eat several times a week. Be prepared to supply large amounts of food. Hatchlings will eat crickets, goldfish, pinkies, and anything else you give it. Larger Niles can be fed rodents, goldfish, crayfish, insects, etc. You should attempt to provide variety in the diet.
Variety helps cover any nutrients that are deficient in any one food item.
Again, an adult will eat a lot of large prey items. Niles need warmth. A basking site of at or above 100 degrees should be provided. Some people even go 120 or more degrees. I aim for 100-105 degrees.