Preheat your oven to 375°F. Add the chopped bacon to a large oven-safe skillet and cook over medium heat until crisp. Remove the bacon from the skillet and place it on a paper towel-lined plate. Leave about 1 tablespoon of bacon grease in the skillet.
Add the ground beef to the same skillet and cook over medium heat until browned, breaking it apart as it cooks. Drain off any excess grease if needed.
Stir in the diced onion and cook for 2–3 minutes, or until softened. Add the minced garlic and cook for about 30 seconds, just until fragrant.
Add the baked beans, BBQ sauce, brown sugar, yellow mustard, Worcestershire sauce, smoked paprika, garlic powder, onion powder, black pepper, and cayenne pepper if using. Stir until everything is well combined.
Let the mixture simmer for 5–7 minutes so the sauce thickens slightly and the flavors come together.
Stir in half of the cooked bacon and 1 cup of shredded cheddar cheese. Mix until the cheese starts to melt into the bean mixture.
Sprinkle the remaining ½ cup cheddar cheese and the Monterey Jack cheese evenly over the top. Transfer the skillet to the oven and bake for 15–20 minutes, or until the cheese is melted and bubbly.
Remove from the oven and top with the remaining crispy bacon and sliced green onions. Serve hot with tortilla chips, corn chips, or toasted bread.