Preheat your oven to 375°F (190°C). Grease a 6x9-inch baking dish and set aside.

In a large skillet, heat the olive oil over medium heat. Add the chopped onion and cook until softened, about 3 minutes. Add the minced garlic and cook for an additional minute.

Stir in the frozen mixed vegetables and cook for another 3-4 minutes until they begin to thaw and are heated through.

Stir in the condensed cream of mushroom soup and sour cream until well combined.

Add the smoked paprika, oregano, salt, and pepper. Cook for 2 minutes.

Pour the vegetable mixture into the prepared baking dish, spreading it out evenly. Arrange the frozen tater tots in a single layer on top of the mixture, covering the entire surface.

Bake in the preheated oven for 30 minutes until the tater tots are golden and crispy.

Remove the casserole from the oven and let it sit for a few minutes. Garnish with chopped fresh parsley, if desired, before serving.