Prepare the stuffing mix according to the packet instructions and set aside to cool.
Meanwhile, place the venison trim, venison liver, and bacon on a cutting board and use a sharp knife to cut into 1-inch pieces and put in a food processor with salt, pepper, sage, rosemary, garlic powder, and onion powder.
Pulse for 30 seconds until minced.
Place the minced meat in a large mixing bowl and add the stuffing. Mix thoroughly.
Dampen your hands or wear gloves, divide and roll the minced meat mixture into 8 evenly-sized balls. Place in the refrigerator while you make the onion gravy.
Preheat the oven to 350 degrees F.
In a large skillet over medium heat, add 2 Tablespoons of the butter, sliced onions, and sugar, and cook until lightly browned and beginning to soften, about 5 minutes.
Stir in flour and cook for 1 minute more. Whisk in broth and Worcestershire sauce and bring to boil. Cook until thickened, about 3 minutes. Remove from the heat, stir in remaining 2 Tablespoons of butter, salt, and pepper.
Bake uncovered in an oven for about 45 minutes until the meatballs reach an internal temperature of 165 degrees F using an instant read meat thermometer.