J.,
First, please take a step back from your post and try to look at it from another person's perspective.
He's not being 'manipulative' or scheming in an adult sense. It's that you have let him get his way and whatever he's done to get him his way (tantrum, crying, refusing food) has worked up until this point. I point this out to you because I want you to see yourself as a strong, authoritative parent who knows what's best for her kids and not as a victim who is being wrapped around Kiddo's dinky finger.
Okay, once you've got that mental image of yourself as the person in charge, do what most of us do: Do NOT buy the problem food. Do not have it in your house, period. Cold turkey on the junk food, today. The levels of sodium in ramen are crazy-high-bad. And can be for the nuggets, too, depending on the brand you are purchasing.
At every meal, you call the shots. Reasonable-sized servings of whole-grain breads or crackers are fine. (Reasonable means just that, they are only one part of what's out for the meal.) Start serving fresh fruit or a bit of applesauce; I offer yogurt to my son as one part of the meal (now that he's older, he only has yogurt as a topping for fresh fruit or berries.). Offer simple veggies on his plate-- carrot coins or sticks (you can offer a bit of ranch dressing or peanut/sun butter to eat these with), red pepper strips, peas (he might like them frozen, my son loves them like this) , a few bits of salad to dip into a dressing. Some kids prefer their veggies raw, others like them cooked, so don't just decide he 'doesn't like them' if you haven't offered them both ways several times.
Cheese is a good protein, and kids don't need much of it. A few cut-up cubes of a mild cheese might work, or cream cheese on good crackers or bread will be fine. Hard boiled eggs-- remove the yolk first, and find out if he'll eat the whites, because most little kids I've cared for don't like the strong taste and crumbly texture of the yolks. Little kids often like scrambled eggs too.
If it were me, I would offer some standard noodle soups, like chicken noodle or grab up a box of veggie broth and some egg noodles, add some veggies and you have a very easy, health soup with so much less sodium and no nitrates.
Now, at meals, I will tell you to do what's worked for me and the children I've cared for over many, many years:
First, NO asking 'do you want this or that?' At this point, your son has been trained to throw a fit when he doesn't get what he wants on his plate, right? (At least, that's what I infer from your post.) So, your job is to put two or three choices on his plate and let him choose *from the plate*, not from the cupboard or fridge. Whether that is a little bit of mac and cheese and some peas and some apple slices or if it's more of a ploughman's plate (good bread with butter, a few slices of cheese, some raw veggies and fruit, hard boiled eggs and a couple of black olives)-- whatever works for your to prepare that's healthy is fine. I'd make sure he has at least one familiar food on the plate (apples are a huge hit, usually, so are cheese cubes or sticks) and set out the good food for him.
At this point, it's up to him if he eats. Your magic words are "this is what I have for you." And then, don't talk about it. Don't try to make him eat it, don't try to talk up the foods he's eschewing, just DO NOT GO BACKWARD.
It will take a week, likely, but what you are doing is setting up a new dynamic. Expect that he may not want to eat at meals and will hold out for snacky foods, so at snack times, you don't want to be serving anything 'fun'. This is the time for simple, wholesome snacks like bread and butter, raisins, cut-up fruit and veggies, cheese. Once again, don't make this a time to 'hold out' for.
Good luck going forward and remember to keep any 'not great' foods out of the house entirely.