I've thought about that idea as well, have some sort of official standard for something to be called news. Requirements about the separation between editorial and objective content, requirements for certain standards of fact checking and confirmation before reporting, etc. If you don't abide by those standards, you don't get official accreditation as a reliable news source. Give it some sort of official seal or recognition so consumers can see that this show or website is trustworthy. Maybe add some tax credits for these sources, or subsidies or grants to give them an additional edge over their competition. We already have the Corporation for Public Broadcasting, maybe we expand the grants made available and provide stricter requirements for eligibility.
All that said, I am ... hesitant about such a system. It would be immensely controversial, and puts a lot more power in the hands of government over the news content Americans watch every day. The only way to assuage my concerns about that is to make the base standards a pretty lower bar, just things about confirming stories and requiring the submission of corrections and redactions when needed. And add in something to protect journalists, so that the government can't revoke a new source's accreditation because they leaked CIA documents about torture or something else embarrassing to the government. Maybe model it more like university accreditation, where accreditation of news sources involves the input from NGOs and regional government entities.
There's also some question about how helpful it would really be: I imagine the people who watch Info Wars aren't going to stop because it doesn't have the government seal of approval. I think you'd need to give a lot in subsidies or benefits to accredited news sources to give them an edge.