In a small bowl, combine mayonnaise, ketchup, pickle juice, and hot pepper sauce. Refrigerate until ready to use.
In a large skillet, cook chopped chuck over medium heat, until no longer pink, 6-8 minutes; drain. Stir in onion powder, salt and pepper. Sprinkle with cheese; cover and let stand until cheese is melted.
Divide beef mixture among tortillas. Top with lettuce, tomato, pickles, and sauce.