Season ground turkey with cajun seasoning, garlic powder, onion powder and chopped onion. When no longer pink, add tomatoes with green chiles, taco seasoning, salsa, black beans, refried beans and mexicorn. Let simmer for 10 minutes.
Preheat oven to 350 degrees, spray bottom of 9 x 13 pan. Pour meat mixture into pan, sprinkle with monterey jack and cheddar cheese. Then top the meat mixture with frozen tater tots. Bake for 30 minutes until tater tots are brown and crunchy. Then add more cheese to the top of tater tots and bake for additional 5 minutes.
When plating, add lettuce, tomato, sour cream and salsa to the top of tater tot and meat mixture.