Eating chiken and oily foods during chikenpox can cause permanent scars?

Not really...: Permanent scars are usually caused by significant skin damage from scratching or from large pox.

No: What you eat during the infection has NOTHING to do with scarring. If you scratch a lot or develop a secondary infection (staph,strep) in the sores they will be deeper and more likely to scar. Any sunburn within 6 months of a case can cause some odd persistence of the superficial scars, but that usually fades in a year or two.