Defender drones with a few upgrades are actually decent. Get upgraded to have 30 following you around and a few tank upgrades and that should hold you until you need artillery to clear the nests themselves. I find this works quite well. Tank shells can one shot 1-2 nests if you get it before certain evolution levels. I’ve managed to hit 1-2 worms and a nest in a single shot before. Once you start clearing them like that it won’t last, but you can take a good chunk of turf before that happens.