Bring a large pot of salted water to a rolling boil. Add the rotini and cook until al dente, about 8-10 minutes. Drain and rinse under cold water.

In a skillet, heat oil over medium heat. Add ground beef and cook for 8-10 minutes until browned. Drain excess fat, add taco seasoning and a splash of water, and cook for another 2 minutes.

In a mixing bowl, combine cooked rotini, browned beef, cherry tomatoes, green onions, cheddar, and Monterey Jack. Pour in Catalina dressing and mix until well coated.

Cover the bowl and refrigerate for at least 4 hours or overnight to let flavors meld.

Before serving, gently stir the salad and fold in Doritos for crunch.