Start by making the Nasi Paste. Add the finely chopped red onion, minced garlic, chopped chilies, shrimp paste, MSG, and salt into a food processor. Pulse until you have a chunky paste.
Heat some oil in a large wok over medium-high heat. Add the shrimp, season with salt, and stir fry for 2 minutes, or until cooked. Transfer the cooked shrimp to a bowl and set aside.
In the same wok, add a bit more oil. Add the Nasi Paste you prepared earlier and stir fry for 10 to 20 seconds, or until fragrant.
Next, add the chopped chicken to the wok and stir fry for 2 to 3 minutes. Add the beansprouts, and continue to stir fry until the beansprouts are al dente and the chicken is fully cooked.
Now, add the cooked rice, Ketchup Manis, cooked shrimp, and sliced spring onions to the wok. Stir to combine everything well.
Meanwhile, heat some oil in a separate saute pan. Crack an egg into the pan and fry for 2-3 minutes, or until cooked to your preference. If you prefer a crispy edge, fry over a medium high heat.
To serve, plate the Nasi Goreng and top with the fried egg. Serve hot.