Preheat the oven 180°C.
Mix the spiralized sweet potato with the flour, oil, oregano, water, salt and pepper.
Divide the mixture between the 4 holes of a deep muffin tin. Using the back of a spoon, press the sweet potato into the base and sides of the tin to form a basket shape. Bake for about 15 minutes.
Remove the tin from the oven and put one half of a tomato and some spring onion bits into each nest, then crack an egg over them. Bake for another 8-10 minutes, or until the egg has just set (if you want the egg yolk runny).
Rest for 2 minutes before carefully scooping the nests from the tin, using a spoon.
Serve warm.