Preheat oven to 375°F (190°C).
In a large skillet over medium-high heat, cook the ground beef until browned, breaking it apart with a spatula, about 5-7 minutes.
Add the diced onion and minced garlic to the skillet and cook until the onion is translucent, about 3-4 minutes.
Drain excess grease from the skillet.
Stir in the frozen mixed vegetables and cook for 3 minutes until slightly thawed.
In a medium bowl, combine the condensed cream of mushroom soup, sour cream, salt, black pepper, dried thyme, and paprika. Mix well.
Pour the soup mixture into the skillet with the beef and vegetables. Stir to combine evenly.
Transfer the beef and vegetable mixture into a 9×13 inch baking dish and spread it out evenly.
Sprinkle the shredded cheddar cheese evenly over the beef mixture.
Arrange the frozen tater tots in a single layer on top of the cheese.
Bake uncovered in the preheated oven for 35-40 minutes, or until the tater tots are golden brown and crispy.
Remove from oven and let the casserole rest for 5 minutes before serving.