Cut the bacon into ½-inch pieces. Add it to a large skillet over medium heat and cook for 8 to 10 minutes, stirring occasionally, until browned and crisp. Transfer the bacon to a paper towel-lined plate to drain.
Add the drained green beans to the slow cooker.
Sprinkle about two-thirds of the chopped bacon over the green beans.
In a small bowl, whisk together the melted butter, brown sugar, soy sauce, Worcestershire sauce, garlic powder, onion powder, and black pepper.
Pour the sauce evenly over the green beans and gently stir until everything is well coated.
Cover and cook on LOW for 2 ½, stirring once about halfway through if possible.
Stir the green beans well before serving, then sprinkle the remaining bacon over the top.