i’m not talking about pre-cooked veggies or things that are part of larger meals…
if i buy a bunch of fresh green beans, steam them, and eat them
is that nutritionally the same as buying a pound bag of frozen cut green beans, steaming them, and eating them?
The vitamins and other nutritional content breaks down over time. Freezing doesn’t stop this. The best will be fresh picked. After picking what you do to them affects how quickly they lose nutritional content. Stopping or slowing the plant’s enzyme reactions is important to preserving nutritional content.
Depending on how long the “fresh” green beans took to get to your store, and how long they were sitting in your refrigerator or pantry before you got to cooking them, and how soon after picking the frozen beans were frozen, and how they were handled on the way to the store, the frozen ones might even be more nutritious. As Harmonious Discord pointed out, all foods deteriorate over time. Freezing can slow this down. Beans frozen just after harvest and kept properly frozen until you use them might well retain more nutrition than “fresh” beans that take a week (or more!) to go from field to your purchase, then sit around another day or two, before being eaten. Poorly handled frozen beans, or those that have been sitting in a freezer for months on end, not so much.
I mean picked that day and hopefully a few hours ago, when I say fresh picked.
Vegetables in the produce section of the store have been picked shipped and then stored for days up to months, depending on the store.
Frozen vegetables are not processed immediately either, and sit in unrefrigerated semitrailers until they get processed and frozen. Don’t imagine they are frozen a couple hours after being picked.
Well, MY frozen vegetables ARE processed an hour or two after picking… but that’s because they are from my own garden. 
Still, a valid point. Much depends on handling and time. As a practical matter there probably is not a great deal of difference. In season, locally produced fresh produce is more likely to have an edge over frozen, whereas frozen might well have an edge over out-of-season, stored-for-months, and distant-import “fresh” food.
i know that some vegetables are canned within hours, like 2 or 3, of being picked. freezing plants might be able to do so also.
in agricultural areas i’ve gone through i see the processing plants right in the growing area, like within an hour drive.
A couple hours from picking to processed is not the norm. Perhaps for the first of the season before things get hectic you’ll see that. You often will see the trailers of picked vegetables sitting in the field for 24 hours.
I have no links to reference, but I’ve always heard frozen or even canned veggies can be more nutritious (if processed quickly) than fresh. But the difference in vitamins isn’t that much, no matter how or if they are processed! Any vegetables are healthy for you, frozen or canned are fine if you don’t have any fresh, and eating a lot of vegetables is good for one’s health.
canneries and harvesting are around the clock operations.
Not that it prevents them from getting backed up.
That shouldn’t be a problem with beans.
In general, freezing modestly reduces the amount water soluble vitamins while soluble vitamins are reduced significantly.
One thing I’d like to see answered regarding this is how MUCH nutritional content is lost? 1%? 99%? Somewhere in the middle? “Fresh is better than frozen” isn’t a very relevant rule of thumb if the actual loss is minute.
And what exactly is meant by nutritional content? Macronutrients? Vitamins? Something else? Is it at all quantifiable? “Hey, those green beans were frozen, you’re not getting as much Vitamin C! Watch out for scurvy!” Not to be snarky or anything but I want specifics 
Wanting detail like this means you need to take a class in school to cover it in depth, because you want to know everything about it apparently. You can’t cover everything in a thread.