Preheat oven to 350 degrees. Coat 11x7 baking dish with cooking spray.
In a large skillet, saute the ground turkey and diced onion until cooked through. Add in the seasoning and saute another 1-2 minutes, then dust with flour and cook for an additional minute.
Add in canned tomatoes and Rotel and simmer mixture gently for 10 minutes, adjust seasoning to taste.
In large bowl combine meat and tomato mixture with tortilla chips, then pour into prepared baking dish. Top with crumbled/shredded cheeses and bake for 10 - 15 minutes until mixture is bubbly and cheese is melted.