Yes, better media coverage would have resulted in Sanders' nomination. Media coverage is important, not only for name recognition and publicity, but for support. In general, people respect the media and believe what they hear on television or the internet. Media coverage equals legitimacy in many cases and for Sanders, may have meant the election.
There is no question that certain presidential candidates this cycle garnered significantly more media coverage than others. Bernie Sanders was not covered by the media nearly as often as Donald Trump and Hillary Clinton have been. The lack of coverage may have hurt his chances for the nomination early on; preventing him from building enough momentum to secure the nomination. In short, yes, better media coverage would have helped Bernie Sanders' campaign.
It is wrong for Sanders to claim that the disconnect between the mainstream media and the public might have cost him the Democrat presidential ticket. As far as coverage is concerned, there was fair and equal coverage on his campaign and to those of Hillary. He should go back to the drawing board and see what it is he did wrong.
Bernie Sanders was not going to win the nomination. Although he claims there is a disconnect between the mainstream media and the public, he was still facing a well financed and organized opponent. He did tap into the anger the electorate is facing, particularly young people. But, it was not enough to gain the nomination.