According to analyst Junko Yamamura of Nomura Securities, Nintendo will reveal their NX console this June, with the full release planned for just prior to the 2016 holiday season at the end of the year.

The firm also believes that the NX will indeed have an impact on the sales of both the 3DS and Wii U, which actually seems super obvious.
We had previously thought that the NX launch would have only a limited impact on 3DS and Wii U sales as it is not being positioned as a successor to either console, but we have now altered our view because 3DS sales have been weakening a little recently, particularly in terms of software, as the machine enters its sixth year, and to factor in a harsher competitive climate and what happened to other existing consoles when new machines were launched in the past.