Unfortunately, no. There isn't any support of the Navionics SonarCharts on the Furuno NavNet series. The TZT2 and 3 are compatible with the CMOR charts, however. It's taken a while for them to convert that data for northern areas, here's a link to see what's available now. CMOR Charts
I'm told they should have the full CMOR database available by Q2 2021.
You know there already is a 'Depth Shading' feature already built into the preloaded NOAA charts; just do an edge swipe from the bottom of the screen and toggle on 'Depth Shading' . You'll notice as you zoom in to an area it'll automatically adjust the bathy exaggeration. Furuno was the first to do this.