Corned Beef Hash Brown Casserole

Name: Corned Beef Hash Brown Casserole
Ingredients: 3 tablespoons vegetable oil, plus more for greasing the baking dish; 6 cups frozen potato tots, from a 32-ounce bag (about 28 ounces); 1 small yellow onion, finely chopped; 1 red bell pepper, finely chopped; 1 green bell pepper, finely chopped; Kosher salt and freshly ground black pepper; 1/2 pound sliced deli corned beef, cut into 1/2-inch pieces; 8 large eggs; 1 1/2 cups whole milk; 3/4 teaspoon dry mustard; 4 dashes hot sauce, or to taste; 1 1/2 cups shredded Cheddar