Seeking a mystery tool to tighten a faucet nut.

[jde682]

Tightened this up by hand, then tightened the screws down. The faucet still has too much play in it. There is no room to get any conventional tool on the nut to tighten it. I bought a faucet tightening tool from Ridgid, but the nut is too big for the tool. Any pros out there know the magic tool for this job?

Sincerely,
Struggling homeowner

 

[Geofd]

There is a tool out there called a basin buddy, it goes on the end of a socket extension

 

[Twowaxhack]

It might be the whole sink flexing