Preheat oven to 450F.
Spray a 9x13 pan with nonstick cooking spray.
Layer ½ the tater tots in the bottom of the dish.
Spray the top of the tots with nonstick spray.
Bake until crispy, roughly 15 minutes. Remove and set aside.
Reduce heat of oven to 350F.
In a large skillet, heat the olive oil over medium high heat.
Cook the onion and bell peppers until softened, roughly 5 minutes.
Add the diced or shredded corned beef and cook another 2-3 minutes.
Remove from heat and set aside.
In a medium bowl, combine the eggs, milk, mustard, and hot sauce.
Whisk to combine and eggs are broken up.
Spread ¾ cup Swiss Cheese over the tater tots.
Spread the corned beef and vegetable mixture and spread into an even layer.
Pour the egg and milk mixture over the corned beef.
Add the remaining tater tots over the top.
Top with the remainder of the Swiss cheese.
Bake for 50-60 minutes or until the egg mixture is set and a light golden brown.
Remove and let cool for 5 minutes.
Serve warm!