Brian Steinberg Senior TV EditorOne of cable’s biggest news outlets has started to fill more of its schedule with something other than traditional news coverage.MSNBC has defined itself for the past few years by using the bulk of its daytime schedule to air breaking reports from NBC News personnel on the news of the moment, then amping up analysis and progressive opinion-making in the early afternoon and evening. Now, as media companies intensify their efforts to attract audiences via streaming video, the business behind the TV home of Joe Scarborough and Nicolle Wallace is in flux.Three different people familiar with the relationship between NBC News and MSNBC — each outlet is supervised by a different top manager — say that some NBC News correspondents have been directed to bring breaking-news coverage first to NBC News Now, the company’s ad-supported streaming news service, or other digital NBC News properties before any appearance on MSNBC is considered.