Toast the bread then top with sliced avocado. Drizzle with oil, season with salt, pepper, and red pepper flakes (if using).
Preheat the oven to 400 degrees. Cook the sausage to an internal temperature of 160°F using a thermometer.
Preheat a non-stick pan over low-medium heat. Once hot, add the remaining oil to the pan. Crack eggs on a flat surface and into the pan being careful not to break the yolk. Cook until the whites of the eggs are firm and no longer runny. Add 1 to 2 tablespoons of water and cover with a lid if desired to help firm the egg whites completely. Season with salt and pepper.
Serve the eggs with avocado toast, sausage, and nectarine.