Heat oven to 400°F; butter metal 9-by-13-inch pan. Keep tots frozen while preparing filling.
Brown sausage in skillet over medium-high 8 to 10 minutes, crumbling finely, to 160°F. Drain fat.
Whisk eggs, milk, salt, and pepper until no egg-white streaks remain. Spread sausage and cheddar in pan; pour eggs over.
Arrange frozen tots in one layer on top. Bake uncovered 40 to 45 minutes until tops brown and center egg mixture reaches 160°F.
Rest 10 minutes; cut eight portions. Egg layer should hold together when lifted.