In a large skillet, cook beef, onion and green pepper over medium heat until meat is no longer pink; drain. Stir in taco seasoning and water. Cook and stir until thickened, about 3 minutes; set aside.
Place chips in a greased 8-in. square baking dish. In a small bowl, stir refried beans; spread over chips. Top with beef mixture and cheese.
Bake, uncovered, at 375° until heated through, 15-20 minutes. Top with lettuce, tomatoes and olives. Serve with sour cream and picante sauce.
