Heat oven to 400℉.
Layer the corn in a hotel pan.
In a bowl, combine the mayonnaise, sour cream, minced onion, chili powder, garlic powder, and salt.
Pour the mayonnaise mixture over the corn and mix until well combined.
Bake at 400℉ for 30 minutes until bubbly throughout and golden brown around the edges and on top. Give the casserole a stir midway through cooking to prevent scorching around the edges.
Serve topped with cilantro and queso fresco cheese.