your'e taking that big of a cycle and you don't know how hcg and tamoxifen work? That's something you probably should have figured out a long time ago.
You should understand that any time you use exogenous hormones, the permanent shutdown of your natural production is a potential outcome. This likelihood increases with length of cycle as well as quality of pct and some other factors. Now, many people have been just fine, even with very long cycles, fully coming back from them. Others are not as lucky.
Not sure where you got that information, but taking nolva with hcg on cycle isn't going to increase your chance of avoiding permanent shutdown. HCG will keep your body sending the signals that your body needs to produce natural test which is helpful in making your body's transition back to natural production easier.
So no, you don't need Nolva on cycle, just continue with HCG 500iu/wk. And hopefully you're using arimidex at .5mg EOD, not 20mg EOD.