@Alexandre. I tired this solution and run into a new problem of it saying I have no connection to the internet now instead as seen above 

  @RobW1 

Sorry to hear this did not work for you. You will need to undo the change, by switching Deco mesh to run in default Router mode. If you can't get access to Deco mesh through Deco app, you may need to reset your Deco mesh and start anew.

How can I reset or reboot my Deco Whole-Home Wi-Fi System?

  @Alexandre. This is hardly an answer on how to get rid of double NAT. It seems like Deco is missing crucial functionality. Telling someone to switch from Router mode to Access point in many cases won't work. There should be a way to open ports, forward traffic for some devices like Xbox to easily get rid of that problem. Telling someone to change the whole network setup, limiting functionality that is one of the advertised advantages of the system is not an answer. 

  @Makusiaga but you can not have two router running on same network.   only one router should have dhcp etc functions to other devices. else two router will create issues.

I'm having this issue with double nat. 

I have a BE65 Pro as main router and mesh system. Wanted to add one near my sons Xbox but not spend as much, did the research and added an x60 since it didn't need to be as powerful and was much more cost effective. 

If I connect the Xbox to that unit wirelessly, no issues and better speed than before. 

If I connect wired directly or with a switch it gives double nat on the Xbox. It does now get 400mb down and 27ms latency vs 90mb and 40ms latency but now have double nat. 

Only routers on my system are deco.