How long do it take for the under view and what could they be reviewing and what comes next
Could you post a screen grab of what you are seeing.
It sound like you have a nomination and Niantic have taken it in to “Internal Review”?
This is quite normal and nothing to worry about, they seem to take some at random and review then in house. When they have finished it could be Accepted, Rejected or returned to the Standard Review queue.
Timescale can vary, it can slow the process down a little depending on the usual timescale in your area but be patient and all will be OK in the end 
Good Luck.
Yes, that confirms that my assumption was correct.
Just a waiting game now.
Good Luck.