Expanded is cannon.

Then star wars universe. Barely. Yuuzhan Vong "tech" would decimate forerunner fleets with Black Holes. Turbolasers outpower anything the UNSC and Covenant have, star destroyers are the same size as Covie ships, in a few standout cases they are bigger. Lightsabers would clash with a Covie energy sword, but that's a "blade" wielded by an enemy who can see the future and has honed his body to react to that power. Force Choke, force lightning, the ability to rip a covie super-carrier out of space and slam it into the ground with one's mind. The force is basically the "i win" button of the Star Wars universe. Spartan II's are the only things that could feasibly move fast enough to counter a jedi, but again the jedi would see it coming. Spartans also can not move faster than the speed of light, and if Expanded universe is canon then what we SEE in the films is the after image of light. Lasers travel at a certain universal constant, something along the lines of 299,792,458 metres per second. That's pretty fast, much faster than the fastest bullet or fastest plasma shot. Given Star Wars' universe has the Yuuzhan Vong, which are decidedly overpowered in every respect, Jedi, and Turbolasers which more than outdo the power output of the biggest mac gun and plasma accelerators of the UNSC and Covenant; the answer is obvious with any amount of math. The chief would probably still somehow survive because how else would Microsoft and 343i make any money off of him, but that's it.

Keep in mind that this is the entire halo universe. That includes all the rings, both arks, the forerunners, and the precursors/flood. I'd say halo has a pretty decent chance at winning.

The flood have an answer in Orbital Bombardment. The rings need humans to activate them (or forerunners) but are a last resort in case everything needs to die. Force Ghosts also can manipulate things in the physical world on a very massive scale. What part of "more powerful than you can possibly imagine" does nobody get? In universe instances of Luke Skywalker's force ghost collapsing stars and remaking solar systems. Halo rings wouldn't exist for very long, especially considering the forerunners would not wish to use them giving any cohesive force a chance to neutralize them. The death stars (all 3) would be immaterial to the battle, as would the halo rings. Both sides have the ability to effectively negate any super weapon pretty much at will. I'd say the only real "super weapon" that would have any impact would be the Eclipse class super star destroyer. But that would likely get destroyed as well.

The flood at its height had control of Ais and a vast former forerunner fleet.