Preheat oven to 400°F (200°C). Grease a 9x13 inch casserole dish.
Heat olive oil in a large skillet or Dutch oven over medium-high heat. Add ground beef and cook until browned, drain excess grease.
Add diced onion, carrots, and celery to the skillet. Cook until vegetables soften, about 5-7 minutes. Add minced garlic and cook for 1 minute until fragrant.
Stir in tomato paste, Worcestershire sauce, dried thyme, salt, and pepper. Cook for 1 minute, stirring constantly.
Pour in beef broth. Bring to a simmer, reduce heat to low, and simmer for 10-15 minutes, until sauce thickens slightly.
Transfer meat mixture to the prepared casserole dish, spreading evenly.
Arrange frozen tater tots in a single layer over the meat mixture.
Bake for 25-30 minutes, or until tater tots are golden brown and crispy and filling is bubbling.
Let cool for a few minutes before serving.