r7200 static routes and AP

> I'm having trouble [...]

   "trouble" is not a useful problem description.  It does not say what
you did.  It does not say what happened when you did it.  As usual,
showing actual actions (commands) with their actual results (error
messages, LED indicators, ...) can be more helpful than vague
descriptions or interpretations.

> [...] when I get on my ATT Fiber router [...]

   Not a very detailed description of that device.  How is it
configured?  To what is it connected?

> [...] from being able to access my private LAN on my Nighthawk.

   What does "my private LAN" mean to you?

> Am I not seting up my static route correctly??

   Can't see it.  Apparently, the moderator did not like your pictures.

   I'd forget any Netgear app, and stick with a web browser.

   If you're cascading multiple routers, then why?  You might be happier
if you configured the inner router (R7200?) as a wireless access point.

   Visit http://netgear.com/support , put in your model number, and look
for Documentation.  Get the User Manual (at least).  Read.  Look for
"Set up the router as a WiFi access point".

   If you really want to cascade the two routers, then the useful static
route would be configured on the _outer_ router, not on the inner router
(R7200).