I would personally enjoy each little story by release date order. Chronological order is too complicated and most novels jump around years like it's going on sale. With release order you get the full experience of witnessing the evolution and the highs and lows of Halo throughout the years just like those who have been with the series for over a decade. Plus it's always nice to feel like major plot points and little teases pay off in the long run instead of jumping straight to it.

There's just one little correction I have to note. The Halo Wars graphic novel, Genesis, was a companion piece released alongside the game that sets itself up as a prequel. It's best to read Genesis first, then play Halo Wars. Nothing in the graphic novel teases anything that happens throughout the game or following the story's conclusion.