A GM might trade players away to speed up a rebuild, and you can consider than tanking, sure. That's on the GM/Front Office side.
On the coaching/players side tanking does not happen in the NFL. Those guys have careers and pride at stake. Ask Lovie Smith and the Texans last year.

Brian Flores' accusations of tanking coming from the owner/GM may be true, but he pushed back on those, privately and publicly. Coaches who finish a season with a bad record to pick Top 5 rarely survive to coach the same team the following season. Many of the players get swept away with that new coaching regime, etc. They want to keep their jobs, they aren't tanking.