dpreview forum member Jorginho created a couple side by side images showing the recently leaked Nikon mirrorless camera sensor next to other sensor sizes. It gives us a visual look at how big a 2.7x sensor actually is. Above, we see the Nikon sensor next to the tiny Pentax Q sensor, which has a crop factor of 5.7x.
Large enough to have much higher quality than compact cameras, but small enough to have a compact camera-sized body. That seems to be what Nikon is aiming for here.