Preheat the oven to 350°F (175°C) and grease a 9x13-inch baking dish.
Bring a large pot of salted water to a boil and cook the jumbo shells until al dente according to package instructions; drain and rinse under cold water to stop cooking, then set aside to cool slightly.
In a large bowl, combine the chopped rotisserie chicken, taco seasoning, room-temperature cream cheese, sliced green onions, thawed corn, salsa, and ½ cup of the shredded Mexican cheese; mix until evenly combined.
Stuff each cooled pasta shell with the chicken mixture and arrange the filled shells in the prepared baking dish in a single layer.
Sprinkle the remaining 1½ cups shredded Mexican cheese evenly over the filled shells.
Bake for 15–20 minutes, or until the filling is warmed through and the cheese is melted and bubbly.
Remove from the oven and garnish with sour cream, halved cherry tomatoes, and fresh cilantro as desired; serve warm.
