A few months ago, I would have said that Trump's accusations that NBC News reports "fake news" would not have any impact on the company or Americans' perceptions of NBC News and the media at large. Now, I think it likely that many will agree with him, based off of the greater support for him than most originally thought.
Trump has been extremely vocal about the "fake news" and has accused many media outlets of producing such news. It seems that each time a news outlet comes out with something that doesn't look good on Trump, he deems them to be uncredible. He is only going to make himself look bad once he has denounced every actual credible news outlet in the world.
It would seem that Donald Trump has made it his personal mission to discredit anybody that says the slightest ill word against him. He may be the president of the United States now but just because he says something does not make it fact. Trump is like that kid on the playground who's only comeback is "you're wrong" when he is backed into a corner. It will take more than words to discredit the media specific groups Trump feels are generating fake news. We would need actually facts to do that job.
Maybe General Motors and Wal-Mart are ramping up planned job creation, but who knows. He hasn't offered any proof for his claims. All Trump does is call names. "Liar, liar, pants on fire." I would love to see him say something that is more mature than kindergarten playground antics and name-calling.