Preheat your oven to 375°F (190°C). Grab a 9x13 inch baking dish and set it aside.
In a large skillet over medium-high heat, brown your ground beef. Break it up with a spoon as it cooks. Once it's no longer pink, drain off any excess grease.
Turn the heat down to low. Add the drained green beans, cream of mushroom soup, and milk to the skillet with the beef. Stir everything together until it's well combined and starts to warm through.
Now, stir in the garlic powder and onion powder. Give it another good stir.
Taste the mixture and add salt and pepper as needed. Remember the soup and cheese have salt, so start with just a little and add more if you think it needs it.
Stir in about half (½ cup) of the shredded cheddar cheese into the beef and bean mixture. This makes the inside extra gooey and cheesy!
Pour the entire mixture from the skillet into your prepared 9x13 inch baking dish, spreading it out evenly.
Arrange the frozen Tater Tots in a single layer over the top of the beef mixture. You can line them up neatly or just scatter them – whatever makes you happy! Make sure the top is mostly covered.
Sprinkle the remaining ½ cup of shredded cheddar cheese over the top of the Tater Tots.
Pop the dish into your preheated oven and bake for 25-35 minutes, or until the casserole is bubbly around the edges and the Tater Tots are golden brown and crispy.
Let it sit for 5-10 minutes before serving. It will be piping hot, and this resting time helps it set slightly.