I was realy surprised to know that our naira is bigger than south Korean money, today i was reading bbc news when i saw one usd is 1,222 in south Korean won, that realy surprised me when one usd is about 791 naira, so our economy is still better than south Korean or is there other ways to say it atually.

It doesn't work like that. Naira might have more value than won, but if they are self sufficient, then their economy will be a lot better than Nigerian economy which depends on imports for econonic survival.

You also need to consider their rate of employment and cost and standard of living in their country before you can conclude that Nigeria is better off which I doubt.