The pleasure’s all mine, anon! Don’t worry, no question like this has been asked before.
There is a plant called a Mire nettle that is definitely the most similar, but it only grows on the planet Nyriaan and it’s processed to make a powerful narcotic, so this may not be what you’re looking for. If you’re hoping to keep with the relative harmlessness of a stinging nettle, your best bet might be a species of cactus or thorny bush, of which there are several that could work. (Feel free to shoot me another ask if you think something like that could work for your purposes).
There are also some plants that aren’t as harmless as a nettle but are still somewhat similar. A flowering, semi-sentient plant called an urchin has spines that it hurls at anyone trying to touch or pick it. The Whinndorian gorsk-plant grows flowers that sting, but these stings are paralysing. You probably have no use for this, but there’s also a plant called a stingwort which has a venom that causes anaphalaxis in humanoids.
I hope that’s at least a little useful! Let me know if I can help more.
EDIT: Make sure to check out the comments for another plant that may work, but note that it most likely only grows on Ithor!
~ Jacen