Prepare gravy and stuffing and set aside.
In heavy bottom Dutch oven or Instapot, fry bacon in 2 tbsp oil until crisp. Remove bacon to paper towel.
On medium-high heat Fry mushrooms and ¼ tsp salt until golden and moisture released.
Remove mushrooms to bowl.
In same pot add drippings, remaining 1 tbsp oil and butter. When bubbling add veg and garlic. Cook over medium heat until onion is translucent and veg starts to soften.
Add in ¾ of the minced herbs. Cook until fragrant, 2 minutes.
Add in cream, gravy, bacon, chicken, mushrooms (and any juices) and stir until combined. Cook until warmed through. Add salt and pepper to taste.
If making ahead (suggest at least one day before to let flavours marry and develop) cool completely and refrigerate for up to 3 days.
When ready to serve, stir in stuffing. Add ½ (or more) chicken broth to loosen the mixture to desired consistency. Heat through and taste and adjust for seasoning.
Warm in crock pot or Instapot.
Serve on buns and top with cranberry sauce (and chives if desired).