Arrange potato nuggets in a single layer on a baking sheet.
Bake in the preheated oven until potato nuggets are partially cooked, 12 to 15 minutes. Remove from oven.
Reduce oven temperature to 375 degrees F (190 degrees C). Spray a 9x13-inch casserole dish with cooking spray.
Heat a large skillet over medium-high heat. Cook and stir sausage, onion, chili powder, basil, and garlic in the hot skillet until sausage is browned and crumbly and onion is soft, 5 to 7 minutes; drain and discard grease.
Whisk eggs and cream together in a bowl until evenly blended; season with pepper.
Arrange partially-cooked potato nuggets in the prepared casserole dish; sprinkle with Cheddar cheese. Spread sausage mixture over cheese layer. Pour egg mixture over sausage layer.
Bake in the preheated oven until set in the middle and lightly browned, 30 to 40 minutes. Allow to cool for 5 minutes before serving.