Not really. Canon didn't really tune for anything much. They don't have the ability to not have the curve fade down at low ISO, they are forced into it.
Also if you compare 6D to D750 then it's only like 1/4 stop better for high ISO DR, that is NOTHING. Even the D810 (which was tuned down a touch to be extra good at low ISO since the base is ISO64 instead of ISO100) is still only like 1/2 stop worse at high ISO. And the Exmor in the A7S which has base set to favor high ISO a bit, I believe has both better low ISO DR (although not by quite as much as the D810) and a tiny bit better at high ISO than the 6D at the same time.
How old is the 6D, how new is the 810 and 750?
My point is clear, Nikon doesn't deserve the over the top hype and praise for DR it receives when their cameras are technically worse than the Canon after ISO 1000. Sure, it's within a 1/4 stop which in practical terms is nothing. So again, why the big praise over Canon for DR?
At low ISO, sure - hence they make good landscape cameras. That is about it.
The general internet impression and buzz over the last couple years has been that Nikon blows away Canon on DR because of the Sony sensor. This is just not true, and has to be put into a proper context.