The Nano version of the Radeon RX Vega cards will feature a narrower PCB with 150 W TDP. A similar PCB is already used by Sapphire for its RX Vega 56 Pulse cards. The only known specs for the Nano cards are the 64 raster operators, the 8 GB HBM2 video memory and the 2048-bit memory buss. The cards are expected to be launched this year, before the arrival of the next gen Navi architecture.
https://www.notebookcheck.net/Radeon-RX-Vega-Nano-cards-could-be-launched-soon.296858.0.html