The best way to get back at Nielsen at this point is to get another job, work both and ride it out.
We are WAY past the point of a walkout fixing anything. Nielsen is done, sweetheart. It will NEVER be back to how it was for the US employees, anyways.
Don’t do anything any Nielsen except clock in or acknowledge you’re “there” but don’t get anything done. Or the bare minimum. It’s practically impossible to get fired at Nielsen. Or at least it takes months.
Get your LinkedIn ready. Work with your team to set up connections and write each other recommendations on there. Write each other letters of recommendations on a document with Nielsen letterhead (search the drive for this, it’s available for anyone).
Utilize chat GPT for this and helping write your LinkedIn descriptions. Spruce up your job title that you had at Nielsen (within reason). Change your status to looking for work. Don’t underestimate LinkedIn!
Be willing to start at another company at a lower level if need-be and work your way up (look at job site reviews to see what people say about being promoted or see how the interview feels when talking about the path forward to promotions) while in this transition phase of “working” both jobs.
While earning two paychecks, pay off your monthly expenses (car payment, large credit card payments, etc.) if possible.
If you get stuck at a lower level position at the new company and then get laid off at Nielsen, hopefully the lower salary will be ok with the lower monthly bills you now have + severance.
At least you have already set yourself up though with a new job and you can give yourself some peace of mind.