1Cook beef in 10-inch skillet over medium heat 8 to 10 minutes, stirring occasionally, until brown; drain.
2Stir salsa into beef. Heat to boiling, stirring constantly; reduce heat to medium-low. Cook 5 minutes, stirring occasionally. Pour beef mixture into large serving bowl.
3Heat taco shells as directed on package. Serve taco shells with beef mixture, lettuce, tomato and cheese.