Convert htaccess apache to nginx

Someone can help me covert the code below to apache nginx

RewriteEngine On
RewriteRule ^([0-9]+)$ /showthread.php?t=$1 [NC,QSA,L]

RewriteRule ^((urllist|sitemap_).*.(xml|txt)(.gz)?)$
vbseo_sitemap/vbseo_getsitemap.php?sitemap=$1 [L]

RewriteCond %{REQUEST_URI}
!(admincp/|modcp/|cron|vbseo_sitemap|api.php)
RewriteRule ^((archive/)?(..php(/.)?))$ vbseo.php [L,QSA]

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}
!/(admincp|modcp|clientscript|cpstyles|images)/
RewriteRule ^(.+)$ vbseo.php [L,QSA]

I know change [L] to Last but what is NC QSA.

Thanks for help!

Posted at Nginx Forum:
http://forum.nginx.org/read.php?2,224658,224658#msg-224658