haxchi doesn't really modify anything important, it just replaces a game with something that can run hbl and apply temporary system patches when run. if you've never messed with nand contents there shouldn't really be anything that could have been broken, it should essentially just revert to a pre-modded state just by uninstalling or formatting the system.
I do insist that you should make sure the browser is working before uninstalling, though. You never know what one may want to do with the system in the future, gotta make sure at least some entry point is available.