Bubba mains, what tips can you give for chases?

If there's no windows around, run at people and rev your chainsaw. Either they go down or you instabreak a pallet. If there's a window, whack them if they're close, saw them if they're not. If they're injured and looking behind them, rev your saw to bait the DH. You can moonwalk with your chainsaw if the survivor is at an unsafe window. You don't have to be directly behind people to saw them any more - a couple of metres away is close enough.