clomid and nolva are both good for PCT, though there is no evidence that stacking them is more effective.
there is considerable dispute as to whether clomid or nolva is better for PCT. most of the clinical research indicates that clomid is. Some internet gurus have pushed nolva, though the clinicals with it are not as good.
good PCT=
SERM (your choice and preference) + AI (aromasin or AIFM preferably- shbg reduction) + HCG (10 days 500iu's/day- some say longer, some say higher- thats just reccomendation)