Cook bacon over medium heat until crispy. Remove and set aside, leaving the grease in the pan.
Saute the onion and garlic in the same skillet for 2 - 3 minutes, until softened and fragrant.
Add the green beans, chicken broth, butter and crumbled bacon. Season with Cajun seasoning, salt and black pepper. Stir to combine.
Cover and simmer on low for 10 minutes. Add the diced potatoes, then continue simmering until the potatoes are tender and the green beans are soft (about 30- 40 total simmer time).
Taste and adjust seasoning if needed. Serve warm.