Cook the bacon in a skillet over medium heat until crispy, then drain on a paper towel and chop into small pieces.
Chop the broccoli into bite-sized florets and dice the red onion. Add them to a large mixing bowl.
Add the mix-ins—chopped walnuts, shredded cheddar, sunflower seeds, and crumbled bacon—into the bowl.
Prepare the dressing by whisking together sour cream, mayo, apple cider vinegar, and sweetener in a small bowl.
Toss everything together in the large bowl until the salad is evenly coated with the dressing.
Refrigerate for at least 30 minutes to let the flavors meld.
Serve chilled and enjoy!