Long article with good suggestions.
We have Purslane in our local area, but I've not seen Stinging Nettle here, in Nevada.
https://www.backdoorsurvival.com/two-super-foods-for-spring-foraging-purslane-stinging-nettle/One warning: Don't pick Purslane near roadways due to possible contamination of Lead from car exhausts.
It is best to grow your own Purslane.
PS: Purslane is an Annual and needs to be grown from seed each year. That means harvesting seed from wild plants or finding a commercial source of seed. If you harvest wild Purslane SEED, don't worry about the contamination noted above, it will be too small to be a problem in the sprouted plant.