Brown the Beef: In a large skillet over medium-high heat, add the ground beef and cook for 5 to 7 minutes, breaking it apart with a spoon as it cooks, until no pink remains and the meat is fully cooked through.
Add the Seasoning: Sprinkle the taco seasoning over the cooked beef and stir in 1/4 cup of water, then simmer for 2 to 3 minutes until the sauce thickens slightly and coats the meat evenly.
Cool the Mixture: Transfer the seasoned beef to a plate and let it cool for about 5 minutes before adding it to the pasta salad to prevent the dressing from becoming too warm.
Cook the Pasta: Bring a large pot of salted water to a rolling boil, add the rotini pasta, and cook according to package directions, typically 8 to 10 minutes, until al dente then drain in a colander and rinse under cold water to stop the cooking process.
Combine the Base: In a large mixing bowl, add the cooled pasta and pour in the Catalina dressing, tossing gently until every piece is coated.
Add the Beef and Vegetables: Fold in the seasoned ground beef, halved cherry tomatoes, sliced green onions, and both cheeses, stirring carefully to distribute ingredients evenly throughout.
Fold in the Doritos: Just before serving, gently fold in the crushed nacho cheese Doritos and fresh cilantro to maintain their crunch and vibrant color.
Chill and Serve: Refrigerate for at least 15 minutes before serving to allow the flavors to meld, or prepare up to 2 hours ahead for an even better taste.