In the past there have been rumblings of Nvidia working on a new Shield Portable. Although there is still no official word on it, another certification, this time for the RRA in South Korea, points to it being something coming soon.
The RRA is the South Korean version of the FCC according to the source for this story. The rumored Portable would presumably feature the Tegra X1 processor, a step up from the Shield Tablet's K1 processor and the same processor being used in Nvidia's upcoming Shield Android TV
Along with the possibility of a new Shield Portable, the Shield Android TV is still set to come out this month. However, Nvidia has kept quiet on what day it will actually be made available. We will just have to play the waiting game for now.