Broken valve cover bolt hole.

[nailer341]

the valve cover gets 7# of torque. it took a hell of a lot more than that to do what you show in the picture.
to answer your question, if there are any threads left in the deeper area, you can remove the broken parts and clean up the remaining threads.
if not, you may be able to build it up with some jbweld, or other similar "cold metal" and tap it.
since it only requires 7# it may work out for you.

 

[VTECin5th]

Lol@B's feedback fix.
I wouldn't trust JB weld on the inside of my head for some reason.

 

[reikoshea]

i dont see why it wouldnt work...weve used jb weld like super glue on a broken throttle body...still works to this day. i dont see why jb weld on the outside would hurt, but id call it a temp fix.