Chams are predators, hunt by sight, and are attracted by prey movement. You can feed chams roaches, flies, superworms, crickets, silkworms, hornworms, etc. but every insect food will need to be alive. Some chams will eat SOME fruit or veggies but they will still need live insects. Sounds like you are out of luck unless you can educate your mom about feeder insects and their care.
If you live in So Cal or So. Fl then you could keep your cham outside for much of the year. But they have to have live feeders and they also need variety. So just crickets wont cut it. Mom's gonna have to give the green light for multiple types of bugs in the house. lol
Tell your mom it's either crickets or roaches. Suddenly crickets will seem delightful.
Seriously though, it won't be healthy for the chameleon if your mom only okays one "pretty" bug, and you expect to be able to feed that all the time. They need to have a variety, and they need to have it often. It seems like it's pretty common for them to go "off" a certain type of bug fed regularly, and then they're on a little hunger strike, and then on from there. It's generally suggested to mix it up every feeding, like crickets one day, silks the next, then butters, then crickets again. Certain types of feeder insects are too fatty or too low in calcium to phospherous ratio to be an every day staple kind of food. Usually the most "stapley" one recommended is the crickets, not cause they're so great on their own, but cause they're the most easily gut-loadable. So you can stuff them with healthy vegetables that are high in calcium or whatever, so you can make them temporarily more balanced and healthy for the chameleon.
Some other bugs you can't gutload easily with all that stuff cause they will normally only eat certain things, like silks with the mulberry leaves or special chow.
Yes there are supplements like calcium or herptivite that you'll be adding as well, but it's best if you gutload and don't have to rely somuch on the artificial supplements cause then you have to start worrying about over supplementing and possible complications from that.
Plus there's different levels of chitin? (think like fibre from their shells) in different bugs. So if you feed only squishy worms, they won't be getting that crunchy fibre that they would by including some crickets or roaches, so that's another reason why it's important to mix it up.
So anyway, that's a few reasons why the variety is important. I know it's not convenient, like getting one big container of butterworms that you can keep in the fridge for weeks or something. It will probably actually be very inconvenient, sourcing small amounts of various bugs every few days. And resisting the temptation to overfeed just cause you got too many and they're going to die before the next scheduled feeding in 2 days or whatever. But if that's what's best for the chameleon, then that's what's going to need to be done if you're planning on keeping one.
Mom's are smart and practical and caring. If you explain the facts behind the necessities for the bugs, and assure her that you'll take extra cautions to be careful with them, maybe she'll come around. It's possible that she just assumed that they weren't necessary and you just wanted to feed crickets cause you thought it would be "cool" to watch it eat a bug. lol.
Try involving her in the process of picking it out, let her name it or something, and then she'll be more vested in what's best for the little guy.