The kecap manis is the thing people forget. A proper bakmi Jawa cart pours it in twice, once when the egg goes in and again at the end, and 20g is 55 calories of pure sugar. The dish is sweet for a reason. The oil is the other invisible number: 15g for one plate is normal, and that is 130 calories before anything else.
The noodles are the bulk at 200g cooked, about 280 calories, more than a mie ayam bowl because Jawa-style uses the thick bakmi. The egg adds 70 and a decent amount of the plate's 22g protein. The chicken is usually kampung chicken shredded thin, maybe 40g, so it is more for taste than protein.
Bakmi Jawa carts in Yogyakarta charge Rp 18,000 to 30,000 and cook on charcoal, one wok per order, which sounds artisanal but does not change the calories. The godhog (soup) version is the same ingredients in broth and lands around 500 because there is less oil and less kecap. The nyemek version (half wet) sits in between at 560.
The emping or kerupuk on the side is another 50 calories, and the free acar (pickled cucumber and chili) is the only thing on the table that is close to zero.