Mystery solved! Kata-kat or tak-a-tak کٹاکٹ is a Pakistani dish, originating in Karachi but now popular all over.
It's hard to identify an authentic Nepali dish, because Nepalis are so good at cooking other people's cuisines! I live near a lot of very authentic Nepali places (serving an immigrant community), and their menus always include some Pakistani stuff, some Bhutanese stuff, as well as the usual Indian stuff (I know a Nepali would fight me on this, but Dal bhat seems a lot like an Indian Thali! And of course achar is eaten all over Bengal and Bangladesh).
Most people don't even realize that Nepalis invented Indian-Chinese food (which is popular around the world)! If I want momo, I just go to any Indian-Chinese restaurant. Even if momo aren't on the menu, they'll always make them!