If your chameleon is an adult, they can go without food for a few days until you find more crickets. Mealworms are bad and can cause problems. If you have absolutely nothing else you can feed a freshly molted mealworm so its skin is white and not hard.
mealworms shells are too hard and can cause impaction when fed too often, they are also pretty fatty like superworms nothing really beneficial comes out of them