Heat a large pot or Dutch oven over medium heat and add the diced bacon.
Cook bacon until crispy, about 8–10 minutes, then remove with a slotted spoon and reserve, leaving 2 tablespoons of bacon fat in the pot.
Add chopped yellow onion and green bell pepper to the bacon fat and sauté until the onion is translucent and peppers have softened, about 5–7 minutes.
Stir in minced garlic and cook just until fragrant, about 1 minute.
Sprinkle in chili powder, ground cumin, and smoked paprika; cook while stirring for about 30 seconds.
Pour in the rinsed and drained pinto beans, undrained diced tomatoes, chicken broth, brown sugar, and apple cider vinegar; stir to combine.
Bring mixture to a gentle simmer over medium-high heat, then reduce heat to low and simmer uncovered for 20–25 minutes, stirring occasionally, until sauce thickens.
Stir most of the reserved crispy bacon bits into the beans, taste, and season with salt and freshly ground black pepper as needed.
Serve beans warm, garnished with remaining bacon bits.