clean the hole, use a jbweld or devcon that is for the application, fill the hole in and re-drill and tap. Your more likely to mess up the block trying to tig or braze the aluminum. If its just one small oil pan bolt the epoxy stuff should hold well to do its job.
I used the JB weld and then installed the bolt like a stud. problem solved. The new timing chain is on. Now I'm just waiting for some o-rings and gaskets from the dealer and I can finish putting it all together