In a large pan, melt the butter, and add the chicken. Cook for about 2 minutes, until opaque, but still not cooked through. Add the onion and cook, stirring, until translucent for 4-5 minutes more.
Add the rice and toss to combine. Cook for few more minutes. Season to taste.
Push the rice to the edges of the skillet, clearing a bare spot. Add the ketchup and stir with a spatula for 30 seconds until lightly caramelized. Now mix the rice and ketchup together. Add the frozen peas and toss for a minute, until heated through. Transfer the rice and chicken mixture to a bowl and keep it warm.
Now we will make two egg crepes. Season the eggs with a pinch of salt. Heat a few drops of the vegetable oil in a skillet, and pour the mixture of one egg into it, swirling to coat the pan in a thin layer. Let cook until the top is set, then put the half of the rice and chicken mixture in the middle of the omelette. Fold both sides over the rice mixture. That's it! Repeat the same with the remaining egg.
Serve with some more ketchup on top. Enjoy!