Prepare all of the ingredients. Preheat oven to 400deg. Start water boiling for pasta.
In a bowl, combine all ingredients for the Salsa. Place in refrigerator until ready to serve.
In a large saute pan over medium high heat, add oil, garlic and onions. Cook for 3 minutes then add green chilies, cumin, chili powder and ground beef. Cook until no longer pink (8-10 minutes). Remove from heat and stir in half of cheese.
Add shells to water once it in boiling. Cook as directed on the package. Drain in colander and rinse with cool water to arrest cooking process.
Being filling each shell with a portion of the ground beef mixture and lining them up in a 13x9 baking dish (coat bottom with cooking spray). Once all shells are full, cover with remaining cheese and place in oven for 20 minutes.
In a small bowl, combine sour cream and taco sauce.
Serve shells with a drizzle of sour cream mixture and a spoonful of salsa on top.