Chop the bacon into 1/2 inch pieces and place in a large, hot skillet over medium heat. Fry until just starting to brown. Do not drain the grease.
Stir in the onions and continue cooking for about 5 minutes, until the onions become translucent and begin to soften.
Pour 1/2 cup of chicken broth into the pan and use a wooden spoon to scrape the bottom of the pan, releasing any browned bits from the pan.
Add the green beans and remaining 2 cups of chicken broth to the pan. Season lightly with a small pinch of salt.
Bring the liquid to a boil, reduce the heat to a simmer, and cook for 45 minutes, stirring in water or additional chicken broth as needed to keep the pan from getting completely dry.
Stir in the canned tomatoes and cook for an additional 15 minutes or until most of the liquid has evaporated and the beans are very tender and nearly fallling apart.
Add salt and pepper, to taste.
Notes
We like to joke that these green beans have been cooked until there are no nutrients left in them. They are super tender and nearly falling apart by the time they are done. If you prefer more firm green beans, you can cook for less time at a higher heat to evaporate the liquid. The liquid boiling out helps infuse the green beans with flavor. Season these lightly in the beginning as the salt does intensify as the chicken broth boils out. It's easier to add more salt at the end than to try to fix green beans that end up too salty. You can skip the canned tomatoes entirely or use fresh tomatoes if you prefer.