In A Small Skillet, Cook Beef Over Medium Heat Until No Longer Pink; Drain. Place Tortilla Chips On A Microwave-Safe Serving Plate. Layer With The Beef, Bacon And Cheese. Microwave, Uncovered, On High For 1-2 Minutes Or Until Cheese Is Melted. Top With Guacamole And Sour Cream. Sprinkle With Tomatoes And Onions If Desired.