Preheat the oven to 350°F (175°C) and lightly coat two small oven-safe ramekins with nonstick cooking spray.
Melt the butter in a small skillet over medium-high heat. Add the diced onion and jalapeño and cook for 3 to 5 minutes, stirring occasionally, until the vegetables begin to soften.
Add the minced garlic and cook for about 1 minute, until fragrant. Remove the skillet from the heat and stir the vegetable mixture into the cooked, crumbled tater tots.
Divide the potato mixture evenly between the two ramekins, gently pressing it into an even layer. Sprinkle the mozzarella cheese over the top.
Crack one egg into each ramekin and season evenly with salt and black pepper. Place the ramekins on a baking sheet for easier handling.
Bake on the middle oven rack for about 5 minutes, then switch the oven to broil. Broil for another 5 to 6 minutes, or until the egg whites are set and the yolks reach your preferred doneness and Serve warm directly in the ramekins or gently slide each egg and potato layer onto a plate.