Preheat your oven to 450°F (232°C). Brush corn tortillas with olive oil, arrange on a baking sheet, and bake for about 10 minutes until golden brown and crispy.

In a medium saucepan over medium heat, combine shredded rotisserie chicken with salsa, taco seasoning, black beans, and corn. Stir well and heat through for about 5 minutes.

Remove crispy tortillas from the oven and spoon about 1/2 cup of chicken mixture onto each tortilla. Sprinkle about 1/4 cup cheese on top.

Return the tostadas to the oven for an additional 5 minutes or until cheese has melted and is bubbly.

Remove tostadas, let cool slightly, and garnish with fresh cilantro and diced tomatoes.