Thank you for your time
I’m not aware of any herbicide that will kill burdock and nettle without killing clover.
There are lots of species of nettles. That’s to say nettles is a common name for many plants. All of them that I’m aware are difficult to control. Depending on how many stems are in the plot it may be best to simply spot treat each stem and then overseed. This may be less expensive and allow a food source to be preserved. I often spot treat weeds in my clover plots.