No — you do not need to be a US citizen or even reside in the US to collect a whistleblower award. Information is what matters most. If the evidence you provide helps the government bring the fraudsters to justice, you may be entitled to an award.
The best whistleblower programs that address EB-5 and immigration-related frauds are the Federal False Claims Act (FCA) and the SEC Whistleblower Program. In recognition of the valuable assistance foreign nationals can provide the US government in fighting fraud, neither whistleblower program has a citizenship or residency requirement. In fact, both programs have awarded foreign nationals in numerous separate cases with multiple million dollar awards. Here is an example of a $30 million award paid to a foreign national through the SEC Whistleblower Program: