Visual Studio 2017 SSRS: Mulitple conditions for an "IIF" statment

Hello,

I am almost finished putting some finishing touches on an SSRS report, and have run into a snag:

I have one field that will populate with 1 of 3 different billing types:

Person, Client, Third Party

Each one has a requirement:

Person must not have an insurance in the insurance field, third party must have an insurance, client must have something else.

I started off with the "iif" statement below:

=iif(Fields!Billing_Type.Value = "Patient",(iif(Fields!Lab_Ins.Value=(Nothing), "Green", "Red")), (iif(Fields!Billing_Type= "Client", (iif(Fields!Lab_Ins=(Nothing), "Red", "Green"))), "Transparent") 

But it wouldn't work so I tried the "Switch" statement below:

=Switch(Fields!Billing_Type.Value = "Patient",(iif(Fields!Lab_Ins.Value(Nothing), "Red","Green")), Fields!Billing_Type = "Third Party",(iif(Fields!Lab_Ins=(Nothing), "Red",...