On the RX100, think you are referring to Clear Zoom which automatically gives it 7.1x and something like 10x if you drop it to 10mp. This is non digital.
As for the Nikon, seems like it will hopefully be a whole new camera with a 1" sensor instead of the current 1/1.7" which is in the G12, P7100, and S100.
I'll be very interested to see what Nikon do with the 7200 as the sensor on the 7100 did not get rave reviews. If it's not better that the G12 and there's no G12 replacement in the shops by mid September I can see myself being tempted by the RX100 as if you drop the pixels from 20mp to 10mp apparently it increases the zoom range from 3.6 to 5.1x . I only just discovered that little tip. Better a camera with at least 5x zoom and 10mp than 20mp and only 3.6 zoom.
So thanks for the news, I'll be watching with baited breath.