Cook the bacon in a skillet over medium heat until crispy. Remove from the skillet, drain on paper towels, and crumble.
In a small bowl, whisk together the sour cream, mayonnaise, apple cider vinegar, and powdered keto sweetener to make the dressing.
In a large serving bowl, combine the chopped broccoli, red onion, shredded cheddar cheese, chopped walnuts, sunflower seeds, and crumbled bacon.
Pour the dressing over the salad and toss to coat evenly.
Serve immediately or cover and refrigerate for up to 2 days.