Have you tried to re-tap it? Obviously longer bolts and another nut may protrude enough to cause tire damage especially if running a 240 or bigger. Only other solution is heli-coil as described or drill and retap to next size, I would drill and retap before using heli-coil I've have 50-50 luck with those holding when you have to remove the bolt again. Sure wish you lived close to me, I'd weld a new nut in for ya.
For as the body apart from the spirit is dead, so also faith apart from works is dead (James 2:26) ESV