For dipping sauce, combine sour cream, mayonnaise, 2 tsp. Ultimate Steak Seasoning, horseradish and chives in a small bowl; mix until well combined. Set aside.
Combine steak cubes and Avocado Oil in a large bowl; toss to coat. Add remaining 2 tsp. Ultimate Steak Seasoning and toss to coat. Thread beef onto skewers. Place on a broiler pan. Broil 8 inches from the broiler until steak reaches desired doneness. (For medium, broil 4-6 minutes.) Serve with dipping sauce.