I'll address the potato issue.
I don't actually agree about patatoes being automatically "too much carbs" and they can definitely fit into a diet, especially if you eat them in the right context.
But the carbohydrates in potatoes are starches. While starches are "complex carbs" that does not put them in the category of something like brown rice for an example. It is not just simple versus complex carbs like it used to be. Some complex carbs, notably starches like potatoes have VERY high GI ratings and of course they would have a high glycemic load and insulin rating.
In fact starches can and will raise your blood sugar faster and higher than some simpler sugars. For many people this is an issue when it comes to controlling and buring fat. I am not saying that I condemn potatoes but I would say they should not be a main source of bulk carbs. But it's going to depend on the person. I myself find potatoes good to go (although I don't eat tons of it) but I am a very low bf person with good insulin sensitivity.
And yes, you can find information that says potatoes have a GI of as low as 65. But you will also find info saying as high as 158! That's higher than the table sugar or white bread reference. Of course it's going to depend on the type of potato and that's going to have to do with the amount of amylopectin starch and how "mature" it is. And remember that the GI is based on a standard amount of available carbs - 50 grams. The average potato serving will contain I'd say around 65 grams or more carbs which will put the glycemic load higher.
Any food can affect different people differently of course but potatoes are going to tend to be on the high side. As far as the protein content, by weight it's pretty negligible for bodybuilding purposes and the amino acid content is such that it is an ok protein source in a varied diet but it contains around 10% of calories as protein. Of course all protein counts. Putting potatoes on a list of protein foods, however, doesn't make a lot of sense, IMO since over-reliance on them as a protein source would mean a whole lot of calories as carbs and shunting aside some higher protein sources.
So for bodybuilding purposes I would concider them as a carb source and not put a whole lot of thought into the protein angle. And keep in mind that I am talking about bodybuilding and not someone who is inactive and not trying to grow...in which case they would probably do pretty well with potatoes and other vegetal sources of protein in terms of protein amount but even that is an issue of some debate.
I agree about nettles being very good for you. And they do contain a high amount of protein in the dried form as compared to other plants....40%. But if you consider the weight of it and the sheer bulk amount you'd have to eat to actually equal a lot of protein....well, let me just say you'd have a stomach ache
. A small amount of it each day or a moderate amount 2 or 3 times a day would be great but they are strong and I wouldn't overdo them as a food source. Too much of a good thing.... But yeah they are very valuable and I have eaten them (I used to be a pretty adventurous vegetarian). They taste a little like spinach once you cook them.