Preheat the oven to 425°F. Boil the pasta shells according to the instructions on the packaging. Once cooked, transfer to an ice water bath to stop the cooking. Keep the shells submerged while making the filling.
In a large skillet over high heat, break up and brown the ground beef. As the beef cooks, add the onion, sweet peppers, and taco seasoning. Cook until the beef is no longer pink and the onions are softened, about 8-10 minutes.
While the meat mixture is still hot, transfer it to a large bowl. Stir in the fresco cheese, cottage cheese, nacho cheese, chives, lime juice, and egg.
Pour the enchilada sauce into a 9x9 baking dish. Drain the shells from the cold water. Use a large spoon to scoop up 1-2 tablespoons of filling and stuff it into each shell.
Place each stuffed shell into the baking dish with the enchilada sauce. Spread the cheddar cheese over the top of the shells.
Bake for 15-20 minutes or until the cheese is melted and the enchilada sauce is bubbling. Allow to cool for 10 minutes.
Prior to serving, top the stuffed pasta shells with shredded lettuce, pico de gallo, and a drizzle of sour cream. Serve warm and enjoy!
