One of my favorite potluck recipes is vegan (except for some of the toppings, which you would simply not include for a fully-vegan meal, and would clearly label and set off to the side for a mixed-diet potluck):
I tend to call it nacho soup, but that might be slightly confusing if you’re not using cheese as a topping. The guiding principle is that if would be good on nachos and good wet and hot, it goes in the soup, if it would be better not soaking in soup for an extended period, it goes on as a topping.
For the soup:
+ beans. I usually use pinto, black, and kidney. If it’s going to be the only/main dish, I use one can of beans per person if doing canned (dry is also possible, but if I’m cooking from dry beans I’m going to make a giant pot with as many beans as I can cook in my largest pot and freeze the extra). (You will probably get some leftovers with the one can per person rule, which is not a problem because this soup reheats and freezes well.) I’ll tend to use black beans, then kidney as the tiebreakers if I’m going to have an uneven ratio (4 cans of beans rather than 3 or 6 would mean 2 cans black beans and 1 can of each of the others), but that’s a personal preference. Add the whole can, don’t drain. If your beans are high-salt enough that you want to rinse some of them, add in some water to replace the bean liquid.
+ spices. I use chili powder, garlic powder, and a lot of cumin. (Check your chili powder for weird ingredients to make sure it’s vegan – it’s a spice blend and not standardized between brands.) You can also use taco seasoning packets, check them for non-vegan ingredients carefully if you do. You could also throw in dehydrated onion if you like onion and aren’t using fresh onions. You can also throw in any other spices that you feel would be tasty when making tacos or nachos. If you are cooking with dried beans, fresh tomatoes, and frozen corn you will also want some salt, add it late in the process to keep the beans tender, but if you are using canned beans you will not need to add salt.
+ corn. I usually use one quarter cup of frozen corn per person. You can also use canned corn, but that has more salt and you have less control over ratios unless you want a partial can of corn open for something else.
+ diced tomatoes. I use a can of diced tomatoes for every 3 or 4 people (or fresh if tomatoes are in season and cheap at the market/abundant in the garden at the time)
+ optional: you could presumably put in peppers and/or onions as well. I don’t, so you’ll have to figure out the best ratios and point in the cooking process for that on your own.
Ideally, let all of this cook for a while (an hour or two) at medium heat until it starts to thicken up. Give it a stir every now and then. Once it thickens, turn down the heat to a lower setting until it’s time to eat, or transfer to a crockpot on low to keep it warm until dinner.
Toppings:
+ Crushed corn chips
If serving non-vegans, also include shredded cheese and sour cream as topping options. Some kind of taco meat (whichever kind of taco meat you want – I’d probably do ground beef with taco seasoning because it’s easiest) is also a good topping if you want a meat-based option.
You can include vegan cheese, vegan sour cream, and/or vegan taco meat if you want to, but the particular vegans I used to feed this to regularly thought it was pretty good with just the chips so I never did since I’d be relying on them to tell me which brands to buy and they said not to.
You can also include any other macho/taco ingredients that seem like they’d go well. One of my regular vegans really disliked avocado, so I never tried guacamole to see if it’d be a good addition, but it might be.