I've read that you get every nutrient your body needs from beans except nician. Rice is heavy with niacin.
A Beans & Rice combination are eaten worldwide.
If you do a search, there are other items that have niacin. My favorite meal is pinto beans, cornbread, spinach (or just greens), tomatoes (fried green or in salsa) and fried potatoes (or okra, or eggplant).