1In blender, place all dressing ingredients. Cover; blend on medium speed 30 seconds or until smooth. Pour into small bowl. Cover; refrigerate until serving time.
2In 12-inch nonstick skillet, heat oil over medium heat. Cook bell peppers and onion in oil 6 minutes, stirring occasionally, until tender. Remove vegetables from skillet; set aside.
3In same skillet, cook beef over medium-high heat 5 to 7 minutes, stirring occasionally, until thoroughly cooked; drain. Add taco seasoning mix and water; heat as directed on package.
4Place 1 cup lettuce on each of 6 plates. Top with beef mixture, vegetables, tomato, cheese and chips. Serve with dressing.