Yes, DE and BT are organic treatments. So are chickens, who may (I stress *may* since I don't have chickens) eat the worms or the worm cocoons in their foraging. But, to protect your plants, a "chicken tractor" would be recommended; this restrains the territory over which the birds can roam as they overturn the ground, searching for those worm cocoons and other delights.
Soap sprays; garlic sprays; vinegar sprays (but be careful: vinegar is an herbicide!)--all these are organic, too. But without knowing what kind of worms we're talking about here, it's difficult to know what to suggest.
I suggest that, when you harvest the tomatillos, you soak them in a sink of slightly salted water. The salt will "encourage" the critters to flee the vegetables, whereupon you can send them (the critters) down the drain and rinse your now-critter-free veggies. I use this method on difficult-to-wash leafy greens like kale, chard, and broccoli, where aphids like to hide. The slightly salted water (I'm talking about 1 tsp. in a 6-inch-deep sink) simply isn't to their liking, and they emerge from the veggies, looking for anyplace else.
Oh, did I mention warm
water? And my sink is maybe half-size of some folks' sinks; it's a divided sink. So if you need to use a dishpan to soak your veggies, that's about the size of my sink.
Give it a try; it can't hurt (you rinse off all the salt) and may help.
Sunset Zone 17, USDA Zone 9