These has been asked in the past, and no, this two species shouldn´t be housed together.
Male N.viridescens amplex anything during breeding season, and they can drown a C.orientalis. There are also many other reasons, like patogen exchange, competition, stress, agression, differences in toxins...
Even if someone, somewhere, has had some "success" housing these two together, it doesn´t mean that disasters can´t happen. Mixing invariably involves risks. It´s your responsability as a keeper to avoid as many risks as possible, not to expose them to new risks.
Both species are fascinating, and if you get any of them, i wish you the best of lucks...but please don´t mix. Also bare in mind that the C.orientalis and N.viridescens that are sold in shops are ALL wild-caught. They are very stressed and many die shortly after being purchased. Specially the WC N.viridescens adapt very badly. Try to find captive bred ones, you won´t regret it.